System and method for data augmentation of feature-based voice data

ABSTRACT

A method, computer program product, and computing system for extracting acoustic metadata from a signal. The signal may be converted from the time domain to the feature domain, thus defining feature-based voice data associated with the signal. The feature-based voice data associated with the signal may be processed based upon, at least in part, the acoustic metadata.

RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.62/988,337, filed on 11 Mar. 2020, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to data augmentation and, more particularly, tosystems and methods for data augmentation of feature-based voice data.

BACKGROUND

Data augmentation allows for the generation of new training data for anymachine learning system by augmenting existing data to represent newconditions. For example, data augmentation has been used to improverobustness to noise and reverberation in various speech processingsystems and applications, and other unpredictable characteristics ofspeech. Conventional approaches to augmenting voice-based includeprocessing audio signals in the time domain with various dataaugmentations. However, processing these time domain signals may revealsensitive or private details within the audio signals. As such, theseaudio signals may be processed in other domains to avoid exposing theircontent. Unfortunately, conventional data augmentation processes areunable to augment audio signals in other domains.

SUMMARY OF DISCLOSURE

In one implementation, a computer-implemented method is executed on acomputing device and includes extracting acoustic metadata from asignal. The signal may be converted from the time domain to the featuredomain, thus defining feature-based voice data associated with thesignal. The feature-based voice data associated with the signal may beprocessed based upon, at least in part, the acoustic metadata.

One or more of the following features may be included. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include qualifying at least a portionof the feature-based voice data associated with the signal for one ormore of training data and adaptation data based upon, at least in part,the acoustic metadata. Processing the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include disqualifying at least a portion of thefeature-based voice data associated with the signal from one or more oftraining data and adaptation data based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more gain-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include performing one or morerate-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more audio feature-based augmentations on atleast a portion of the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata. Processingthe feature-based voice data associated with the signal based upon, atleast in part, the acoustic metadata may include performing one or morereverberation-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.

In another implementation, a computer program product resides on acomputer readable medium and has a plurality of instructions stored onit. When executed by a processor, the instructions cause the processorto perform operations including extracting acoustic metadata from asignal. The signal may be converted from the time domain to the featuredomain, thus defining feature-based voice data associated with thesignal. The feature-based voice data associated with the signal may beprocessed based upon, at least in part, the acoustic metadata.

One or more of the following features may be included. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include qualifying at least a portionof the feature-based voice data associated with the signal for one ormore of training data and adaptation data based upon, at least in part,the acoustic metadata. Processing the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include disqualifying at least a portion of thefeature-based voice data associated with the signal from one or more oftraining data and adaptation data based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more gain-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include performing one or morerate-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more audio feature-based augmentations on atleast a portion of the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata. Processingthe feature-based voice data associated with the signal based upon, atleast in part, the acoustic metadata may include performing one or morereverberation-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.

In another implementation, a computing system includes at least oneprocessor and at least one memory architecture coupled with the at leastone processor. The at least one processor is configured to extractacoustic metadata from a signal. The at least one processor is furtherconfigured to convert the signal from the time domain to the featuredomain, thus defining feature-based voice data associated with thesignal. The at least one processor is further configured to process thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.

One or more of the following features may be included. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include qualifying at least a portionof the feature-based voice data associated with the signal for one ormore of training data and adaptation data based upon, at least in part,the acoustic metadata. Processing the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include disqualifying at least a portion of thefeature-based voice data associated with the signal from one or more oftraining data and adaptation data based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more gain-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata. Processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata may include performing one or morerate-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata. Processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata mayinclude performing one or more audio feature-based augmentations on atleast a portion of the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata. Processingthe feature-based voice data associated with the signal based upon, atleast in part, the acoustic metadata may include performing one or morereverberation-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will become apparent from the description, the drawings, andthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a data augmentation process and anspeech processing process coupled to a distributed computing network;

FIG. 2 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIG. 3 is a diagrammatic view of the extraction of acoustic metadatafrom an audio signal according to one implementation of the dataaugmentation process of FIG. 1;

FIG. 4 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIG. 5 is a diagrammatic view of one or more gain-based augmentationsperformed on feature-based voice data according to one implementation ofthe data augmentation process of FIG. 1;

FIG. 6 is a diagrammatic view of a microphone array deployed in anacoustic domain while a speaker is speaking according to oneimplementation of the data augmentation process of FIG. 1;

FIG. 7 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIG. 8 is a diagrammatic view of one or more rate-based augmentationsperformed on feature-based voice data according to one implementation ofthe data augmentation process of FIG. 1;

FIG. 9 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIG. 10 is a diagrammatic view of one or more audio feature-basedaugmentations performed on feature-based voice data according to oneimplementation of the data augmentation process of FIG. 1;

FIG. 11 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIG. 12 is a diagrammatic view of one or more reverberation-basedaugmentations performed on feature-based voice data according to oneimplementation of the data augmentation process of FIG. 1;

FIG. 13 is a diagrammatic view of the training of a filter forperforming one or more reverberation-based augmentations performed onfeature-based voice data according to one implementation of the dataaugmentation process of FIG. 1;

FIG. 14 is a flow chart of one implementation of the data augmentationprocess of FIG. 1;

FIGS. 15-16 are diagrammatic views of machine learning models accordingto one implementation of the data augmentation process of FIG. 1; and

FIG. 17 is an example diagrammatic view of a client electronic device ofFIG. 1 according to one or more example implementations of thedisclosure.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, there is shown data augmentation process 10that may reside on and may be executed by a computing device 12, whichmay be connected to a network (e.g., network 14) (e.g., the internet ora local area network). Examples of computing device 12 (and/or one ormore of the client electronic devices noted below) may include, but arenot limited to, a personal computer(s), a laptop computer(s), mobilecomputing device(s), a server computer, a series of server computers, amainframe computer(s), or a computing cloud(s). Computing device 12 mayexecute an operating system, for example, but not limited to, Microsoft®Windows®; Mac® OS X®; Red Hat® Linux®, or a custom operating system.(Microsoft and Windows are registered trademarks of MicrosoftCorporation in the United States, other countries or both; Mac and OS Xare registered trademarks of Apple Inc. in the United States, othercountries or both; Red Hat is a registered trademark of Red HatCorporation in the United States, other countries or both; and Linux isa registered trademark of Linus Torvalds in the United States, othercountries or both).

As will be discussed below in greater detail, a data augmentationprocess, such as data augmentation process 10 of FIG. 1, may extractacoustic metadata from a signal. The signal may be converted from thetime domain to the feature domain, thus defining feature-based voicedata associated with the signal. The feature-based voice data associatedwith the signal may be processed based upon, at least in part, theacoustic metadata.

The instruction sets and subroutines of data augmentation process 10,which may be stored on storage device 16 coupled to computing device 12,may be executed by one or more processors (not shown) and one or morememory architectures (not shown) included within computing device 12.Storage device 16 may include but is not limited to: a hard disk drive;a flash drive, a tape drive; an optical drive; a RAID array; a randomaccess memory (RAM); and a read-only memory (ROM).

Network 14 may be connected to one or more secondary networks (e.g.,network 18), examples of which may include but are not limited to: alocal area network; a wide area network; or an intranet, for example.

Data augmentation process 10 may be a stand-alone application thatinterfaces with an applet/application that is accessed via clientapplications 22, 24, 26, 28, 66. In some embodiments, data augmentationprocess 10 may be, in whole or in part, distributed in a cloud computingtopology. In this way, computing device 12 and storage device 16 mayrefer to multiple devices, which may also be distributed throughoutnetwork 14 and/or network 18.

Computing device 12 may execute a speech recognition application (e.g.,speech recognition application 20), examples of which may include, butare not limited to, automated speech recognition (ASR) programs andapplications, speech-to-text (SST) programs and applications, computerspeech recognition programs and applications, voice recognition programsand applications, in-vehicle voice command programs and applications,etc. including those available from Nuance Communications, Inc. ofBurlington, Mass. Data augmentation process 10 and/or speech recognitionapplication 20 may be accessed via client applications 22, 24, 26, 28,68. Data augmentation process 10 may be a stand-alone application, ormay be an applet/application/script/extension that may interact withand/or be executed within speech recognition application 20, a componentof speech recognition application 20, and/or one or more of clientapplications 22, 24, 26, 28, 68. Speech recognition application 20 maybe a stand-alone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within data augmentation process 10, a component of dataaugmentation process 10, and/or one or more of client applications 22,24, 26, 28, 68. One or more of client applications 22, 24, 26, 28, 68may be a stand-alone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within and/or be a component of data augmentation process 10and/or speech recognition application 20. Examples of clientapplications 22, 24, 26, 28, 68 may include, but are not limited to,applications that receive queries to search for content from one or moredatabases, servers, cloud storage servers, etc., a textual and/or agraphical user interface, a customized web browser, a plugin, anApplication Programming Interface (API), or a custom application. Theinstruction sets and subroutines of client applications 22, 24, 26, 28,68 which may be stored on storage devices 30, 32, 34, 36, coupled toclient electronic devices 38, 40, 42, 44 may be executed by one or moreprocessors (not shown) and one or more memory architectures (not shown)incorporated into client electronic devices 38, 40, 42, 44.

Storage devices 30, 32, 34, 36, may include but are not limited to: harddisk drives; flash drives, tape drives; optical drives; RAID arrays;random access memories (RAM); and read-only memories (ROM). Examples ofclient electronic devices 38, 40, 42, 44 (and/or computing device 12)may include, but are not limited to, a personal computer (e.g., clientelectronic device 38), a laptop computer (e.g., client electronic device40), a smart/data-enabled, cellular phone (e.g., client electronicdevice 42), a notebook computer (e.g., client electronic device 44), atablet (not shown), a server (not shown), a television (not shown), asmart television (not shown), a media (e.g., video, photo, etc.)capturing device (not shown), and a dedicated network device (notshown). Client electronic devices 38, 40, 42, 44 may each execute anoperating system, examples of which may include but are not limited to,Microsoft® Windows®; Mac® OS X®; Red Hat® Linux®, Windows® Mobile,Chrome OS, Blackberry OS, Fire OS, or a custom operating system.

One or more of client applications 22, 24, 26, 28, 68 may be configuredto effectuate some or all of the functionality of data augmentationprocess 10 (and vice versa). Accordingly, data augmentation process 10may be a purely server-side application, a purely client-sideapplication, or a hybrid server-side/client-side application that iscooperatively executed by one or more of client applications 22, 24, 26,28, 68 and/or data augmentation process 10.

One or more of client applications 22, 24, 26, 28, 68 may be configuredto effectuate some or all of the functionality of speech recognitionapplication 20 (and vice versa). Accordingly, speech recognitionapplication 20 may be a purely server-side application, a purelyclient-side application, or a hybrid server-side/client-side applicationthat is cooperatively executed by one or more of client applications 22,24, 26, 28, 68 and/or speech recognition application 20. As one or moreof client applications 22, 24, 26, 28, 68 data augmentation process 10,and speech recognition application 20, taken singly or in anycombination, may effectuate some or all of the same functionality, anydescription of effectuating such functionality via one or more of clientapplications 22, 24, 26, 28, 68, data augmentation process 10, speechrecognition application 20, or combination thereof, and any describedinteraction(s) between one or more of client applications 22, 24, 26,28, 68 data augmentation process 10, speech recognition application 20,or combination thereof to effectuate such functionality, should be takenas an example only and not to limit the scope of the disclosure.

Users 46, 48, 50, 52 may access computing device 12 and dataaugmentation process 10 (e.g., using one or more of client electronicdevices 38, 40, 42, 44) directly or indirectly through network 14 orthrough secondary network 18. Further, computing device 12 may beconnected to network 14 through secondary network 18, as illustratedwith phantom link line 54. Data augmentation process 10 may include oneor more user interfaces, such as browsers and textual or graphical userinterfaces, through which users 46, 48, 50, 52 may access dataaugmentation process 10.

The various client electronic devices may be directly or indirectlycoupled to network 14 (or network 18). For example, client electronicdevice 38 is shown directly coupled to network 14 via a hardwirednetwork connection. Further, client electronic device 44 is showndirectly coupled to network 18 via a hardwired network connection.Client electronic device 40 is shown wirelessly coupled to network 14via wireless communication channel 56 established between clientelectronic device 40 and wireless access point (i.e., WAP) 58, which isshown directly coupled to network 14. WAP 58 may be, for example, anIEEE 800.11a, 800.11b, 800.11g, Wi-Fi®, and/or Bluetooth™ (includingBluetooth™ Low Energy) device that is capable of establishing wirelesscommunication channel 56 between client electronic device 40 and WAP 58.Client electronic device 42 is shown wirelessly coupled to network 14via wireless communication channel 60 established between clientelectronic device 42 and cellular network/bridge 62, which is showndirectly coupled to network 14. In some implementations, audio recordingdevice 64 may be wirelessly coupled to network 14 via wirelesscommunication channel 66 established between client electronic device 42and cellular network/bridge 62, which is shown directly coupled tonetwork 14. Storage device 70 may be coupled to audio recording system64 and may include but is not limited to: hard disk drives; flashdrives, tape drives; optical drives; RAID arrays; random access memories(RAM); and read-only memories (ROM). User 72 may access computing device12 and data augmentation process 10 (e.g., using one or more of audiorecording system 64) directly or indirectly through network 14 orthrough secondary network 18.

Some or all of the IEEE 800.11x specifications may use Ethernet protocoland carrier sense multiple access with collision avoidance (i.e.,CSMA/CA) for path sharing. The various 800.11x specifications may usephase-shift keying (i.e., PSK) modulation or complementary code keying(i.e., CCK) modulation, for example. Bluetooth™ (including Bluetooth™Low Energy) is a telecommunications industry specification that allows,e.g., mobile phones, computers, smart phones, and other electronicdevices to be interconnected using a short-range wireless connection.Other forms of interconnection (e.g., Near Field Communication (NFC))may also be used.

The Data Augmentation Process:

In some implementations consistent with the present disclosure, systemsand methods may be provided for data augmentation of feature-based voicedata. As discussed above and in some implementations, data augmentationallows for the generation of new training data for a machine learningsystem by augmenting existing data to represent new conditions. Forexample, data augmentation has been used to improve robustness to noiseand reverberation, and other unpredictable characteristics of speech ina real world deployment (e.g., issues and unpredictable characteristicswhen capturing speech signals in a real world environment versus acontrolled environment). Conventional approaches to augmentingvoice-based data include processing audio signals in the time domainwith various data augmentations. However, processing these audio signalswith data augmentations in the time domain may reveal sensitive orprivate details within the audio signals. As such, these audio signalsmay be processed in other domains to avoid exposing their content.Unfortunately, conventional data augmentation processes are unable toaugment audio signals in other domains. For example and as will bediscussed in greater detail below, data retention and privacy agreementsand laws generally require the dashing (i.e., chunking of audio intosmall segments) and de-identifying (i.e., removal of personalinformation) of audio signals. Accordingly, with an audio signal that isconverted to the feature domain, dashed, and de-identified, conventionaldata augmentation techniques are unable to augment the featurerepresentation of the audio signal.

Feature-Based Voice Data Processing with Acoustic Metadata

As discussed above and referring also at least to FIGS. 2-17, dataaugmentation process 10 may extract 200 acoustic metadata from a signal.The signal may be converted 202 from the time domain to the featuredomain, thus defining feature-based voice data associated with thesignal. The feature-based voice data associated with the signal may beprocessed 204 based upon, at least in part, the acoustic metadata.

In some implementations, data augmentation process 10 may extract 200acoustic metadata from a signal. Referring to the example of FIG. 3 andin some implementations, data augmentation process 10 may receive asignal (e.g., audio signal 300). In some implementations, the signal(e.g., audio signal 300) may be an audio recording (e.g., received fromor captured by an audio recording system (e.g., audio recording system64)). In some implementations, audio signal 300 may include speechcomponents and/or noise components. For example, audio signal 300 may bea recording of a speaker's interaction with a virtual assistant. In thisexample, suppose the speaker asks the virtual assistant to check theweather tomorrow and that audio signal 300 is recorded using thespeaker's smartphone; specifically the smartphone's speakerphone whilethe speaker is driving in a vehicle on the highway. Accordingly, audiosignal 300 may include speech components from the speaker; noisecomponents from the vehicle; reverberation (or lack thereof) resultingfrom the vehicle interior; and other acoustic characteristics associatedwith audio signal 300. In some implementations, it may be desirable touse audio signal 300 for training a speech processing system (e.g., anautomated speech recognition (ASR) system, a voice biometric system,emotion detection system, medical symptom detection symptom, hearingenhancement system, etc.) by augmenting portions of audio signal 300.

However and as discussed above, performing these augmentations usingconventional data augmentation techniques require processing andretaining the audio signal 300 in the time domain. When an audio signalis augmented in the time domain, the speech content of the audio signalis exposed. Returning to the above example, processing audio signal 300in the time domain would expose the content of the speaker'sconversation (e.g., the interaction with the speaker's virtual assistantregarding the weather). As will be discussed in greater detail below,data augmentation process 10 may convert 202 audio signal 300 from thetime domain to the feature domain and process 204 the feature-basedvoice data associated with the signal in the feature domain withoutexposing the speech content of signal 300.

In some implementations, data augmentation process 10 may extract 200acoustic metadata from the audio signal before converting 202 the audiosignal from the time domain to the feature domain. Acoustic metadata maygenerally refer to information regarding the characteristics orproperties of the signal. In some implementations, the acoustic metadatamay only refer to properties of the signal without exposing ordescribing any speech content of the signal. Referring again to FIG. 3and in some implementations, data augmentation process 10 may extractglobal acoustic metadata for the signal and/or for portions of thesignal specifically. Global acoustic metadata may include properties orcharacteristics of a signal generally. For example and continuing withthe above example of audio signal 300, data augmentation process 10 mayextract global acoustic metadata for audio signal 300 generally (e.g.,global acoustic metadata 302 associated with audio signal 300). In thisexample, data augmentation process 10 may extract 200 global acousticmetadata 302 indicative of a noise component throughout the entirety ofaudio signal 300 (e.g., noise associated with the vehicle travellingdown the highway while a speaker is interacting with the virtualassistant). While an example of a constant noise component has beenprovided for global acoustic metadata 302, it will be appreciated thatany property or characteristic concerning the audio signal generally maybe extracted as global acoustic metadata 302 within the scope of thepresent disclosure. For example, global acoustic metadata may includeinformation associated with the acoustic domain(s) the audio signal isrecorded in, the number of speakers identifiable in the audio signal,whether the audio signal includes speech and/or noise, the type of audiorecording equipment used to capture the audio signal, etc.

In some implementations, data augmentation process 10 may extract 200acoustic metadata associated with specific portions of an audio signal.Referring again to the example of FIG. 3 and continuing with the aboveexample, data augmentation process 10 may divide audio signal into aplurality of portions or frames. In some implementations, the size ofeach portion or frame may represent a threshold percentage of audiosignal 300, a threshold duration of audio signal 300, a threshold amountof data from audio signal 300, etc. In this manner, audio signal 300 maybe divided into any number of portions within the scope of the presentdisclosure. In some implementations, data augmentation process 10 maydivide the signal into any number of portions of varying sizes and/or ofthe same size within the scope of the present disclosure.

As shown in the example of FIG. 3, data augmentation process 10 maydivide audio signal into e.g., 14 sections or portions and may extract200 acoustic metadata from each portion (e.g., acoustic metadata 304,306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330). Insome implementations, data augmentation process 10 may extract 200acoustic metadata from at least one of the defined portions of audiosignal 300. In one example, acoustic metadata 304, 306, 308, 310, 326,328, 330 may indicate the presence of a speech component while acousticmetadata 312, 314, 316, 318, 320, 322, 324 may indicate a lack of aspeech component. While an example of acoustic metadata indicative ofthe presence or absence of a speech component has been described, itwill be appreciated that any acoustic metadata specific to a particularportion of audio signal 300 may be extracted 200 within the scope of thepresent disclosure. In some implementations, data augmentation process10 may store the extracted acoustic metadata (e.g., acoustic metadata302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328,330) in a memory buffer or other storage device (e.g., storage device16). As will be discussed in greater detail below, acoustic metadataextracted from a signal may be used for processing the signal when thesignal has been converted into the feature domain.

In some implementations, data augmentation process 10 may convert 202the signal from the time domain to the feature domain, thus definingfeature-based voice data associated with the signal. Referring again tothe example of FIG. 3 and in some implementations, data augmentationprocess 10 may convert 202 audio signal 300 from the time domain to thefeature domain, thus defining feature-based voice data associated withaudio signal 300 (e.g., feature-based voice data 332). As is known inthe art, the feature domain may generally include a featurerepresentation of data (e.g., the frequency domain, the Mel-frequencydomain, the Mel Filter Bank domain, etc.). In some implementations,audio signals may be recorded or captured in the time domain (e.g., as afunction of amplitude of the signal over time) with various acousticproperties (e.g., speech components, noise components, reverberation,etc.) stored within the signal. As is known in the art, by convertingthe audio signal to another domain (e.g., the frequency domain, themodulation domain, the Mel-frequency domain, etc.), speech processingsystems may be able to process the speech to perform various functionsthat are not possible in the time domain and/or are more efficient whenprocessed in another domain.

In some implementations, data augmentation process 10 may convert 202the signal from the time domain to the feature domain by obtainingfrequency components from the signal. In some implementations, dataaugmentation process 10 may obtain the frequency components from thesignal by applying a Short-Time Fourier Transform (STFT) to the signal.While a STFT is discussed as a way of obtaining frequency componentsfrom the signal, it will be appreciated that other transformations maybe used to derive the frequency components from the signal within thescope of the present disclosure. Applying a STFT to a signal may includeapplying overlapped framing with an analysis window. For example, audiosignal 300 may be recorded as a time waveform in the time domain. Dataaugmentation process 10 may convert the time waveform of audio signal300 into a sequence of short excerpts or frames (e.g., 20 milliseconds)of the time waveform. Data augmentation process 10 may convert each ofthe short excerpts to the frequency domain by applying a Fouriertransform in combination with a window function, where such windowfunctions are known in the art. Additionally, one or more band-passfilters may be applied and the received speech signal may be convertedby data augmentation process 10 to a plurality of speech signals for aplurality of frequency bands. The frequency bands or frequency bins fromthe Fourier transform may be combined with the time windows to form aplurality of time frequency spectrum cells. The power or amplitude ofthe speech signals may be defined relative to time and frequency in eachthe time frequency spectrum cells, thus defining a power spectrum.

In one example, data augmentation process 10 may convert 202 the signalfrom the time domain to the Mel Filter Bank (MFB) domain. As is known inthe art, converting 202 a signal to the Mel Filter Bank domain includescomputing filter banks by applying triangular filters on a Mel-scale tothe power spectrum discussed above. In this manner, a signal convertedto the Mel Filter Bank domain may include a spectrogram as a function offrequency and time that emphasizes the non-linear human ear perceptionof sound. As is known in the art, a signal may be defined in the MelFilter Bank domain as a plurality of filter banks and filter bankcoefficients. In some implementations, to balance the spectrum andimprove the signal-to-noise ratio (SNR), data augmentation process 10may subtract the mean of each coefficient from all frames of the filterbanks to yield mean-normalized filter banks. In some implementations,these mean values may be stored for reference. In this example,feature-based voice data 332 may include the filter banks and/or filterbank coefficients of the signal in the Mel Filter Bank domain.

In another example, data augmentation process 10 may convert 202 thesignal from the time domain to the Mel-Frequency Cepstral (MFC) domainby computing the Mel-Frequency cepstral coefficients (MFCC) for thesignal. As is known in the art, converting a signal to the Mel-FrequencyCepstral domain includes applying a Discrete Cosine Transform (DCT) tode-correlate the filter bank coefficients as discussed above to yield acompressed representation of the filter banks. The Mel-Frequencycepstral coefficients may include the amplitudes of the resultingspectrum. In this example, feature-based voice data 332 may include theMel-Frequency cepstral coefficients of the signal in the Mel-FrequencyCepstral domain.

While examples of particular feature domains (e.g., feature-basedrepresentations of data) have been described, it will be appreciatedthat data augmentation process 10 may convert 202 the signal from thetime domain to any feature domain within the scope of the presentdisclosure.

In some implementations, data augmentation process 10 may partition ordash a signal to avoid the speech content of the signal from beingaccessed after converting 202 to the feature domain. For example, dataaugmentation process 10 may chunk audio signal 300 into a plurality ofportions and de-identify the portions. These portions may then be storedin a distributed manner without any information linking the variousportions together. In this manner, the speech content of audio signal300 may be kept private while still allowing access to a feature-basedrepresentation (e.g., feature-based voice data 332) of audio signal 300.As will be discussed in greater detail below, without accessing thecomplete or a large portion of an audio signal, conventional dataaugmentation techniques are unable to augment feature-based voice data.For example and as discussed above, when audio signals are dashed andde-identified, conventional data augmentation techniques are unable toaugment the feature domain representation of these dashed andde-identified portions of the audio signal.

In some implementations, data augmentation process 10 may process 204the feature-based voice data associated with the signal based upon, atleast in part, the acoustic metadata. As discussed above and in someimplementations, conventional data augmentation techniques are unable toaugment an audio signal without processing the audio signal in the timedomain and, as such, exposing the speech content of the audio signal.Accordingly, data augmentation process 10 may process 204 thefeature-based voice data associated with the signal (e.g., the featuredomain representation of the signal) by augmenting the feature-basedvoice data. As discussed above, data augmentation may generally includethe process of modifying various characteristics of a particular portionof data. In some implementations, augmented data may help train or adaptmachine learning models and artificial intelligence systems to be morerobust to certain acoustic changes. For example, an automated speechrecognition (ASR) system may be trained with speech signals captured ina noise-free acoustic domain or environment. However, when the ASRsystem attempts to process speech signals captured in an acoustic domainwith noise, the ASR system may be less effective because of the addednoise. In some implementations, data augmentation process 10 may augmentexisting data (e.g., audio signals) to train speech processing systemsto be more robust to these changes and/or to adapt to different acousticdomains. In another example, a part of a speech processing system ormodel may be adapted with new adaptation data. Accordingly, dataaugmentation process 10 may process 204 the feature-based voice dataassociated with the signal to augment data that may adapt speechprocessing systems with new adaptation data.

In some implementations and as will be discussed below, when a signal isconverted 202 from the time domain to the feature domain, it may not bepossible to determine the acoustic properties or characteristics of thesignal without converting the signal back into the time domain.Accordingly, data augmentation process 10 may utilize the extractedacoustic metadata to process 204 the feature-based voice data associatedwith a signal without converting the signal back into the time domain.In this manner, data augmentation process 10 may process 204feature-based voice data associated with the signal without exposingspeech content within the signal.

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include qualifying 206 at least a portion of thefeature-based voice data associated with the signal for one or more oftraining data and adaptation data based upon, at least in part, theacoustic metadata. For example, data augmentation process 10 may utilizethe acoustic metadata to qualify feature-based voice data for variouspurposes (e.g., for training a speech processing system, for augmentingthe feature-based voice data, etc.). In some implementations, dataaugmentation process 10 may receive various constraints to qualify thefeature-based voice data for processing. In one example, dataaugmentation process 10 may receive one or more constraints associatedwith processing 204 feature-based voice data. Data augmentation process10 may compare the one or more constraints to the extracted acousticmetadata associated with the signal to determine whether feature-basedvoice data associated with the signal is qualified for a particular task(e.g., training a speech processing system, adapting a part of speechprocessing system with new adaptation data, augmenting the feature-basedvoice data, etc.).

Returning to the above example, suppose feature-based voice data 332 isthe feature domain representation of audio signal 300 recording a user'sinteraction with a virtual assistant. In this example, suppose a speechprocessing system is only initially trained to process speech signalswith a user speaking directly into the microphone of a telephone. Insome implementations, the speech processing system may be trained toprocess speech signals in other acoustic domains. In this example, dataaugmentation process 10 may receive one or more constraints associatedwith processing feature-based voice data to determine whether the speechprocessing system can or should be trained with feature-based voice data332. Data augmentation process 10 may utilize acoustic metadata 302,304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330 toqualify 206 feature-based voice data 332 for training the speechprocessing system based upon, at least in part, the one or moreconstraints received.

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include disqualifying 208 at least a portion of thefeature-based voice data associated with the signal from one or more oftraining data and adaptation data based upon, at least in part, theacoustic metadata. Continuing with the above example, suppose that theaudio signal 300 includes a recording of a portion of a telephone call.In this example, suppose that the first half of the meeting has nospeech (e.g., silence). In this example, data augmentation process 10may extract acoustic metadata 304, 306, 308, 310, 312, 314, 316 forportions of audio signal 300 that do not include any speech componentand acoustic metadata 318, 320, 322, 324, 326, 328, 330 for portions ofaudio signal 300 that do include a speech component. Data augmentationprocess 10 may process 204 feature-based voice data 332 with acousticmetadata 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324,326, 328, 330. Suppose that data augmentation process 10 receives one ormore constraints for e.g., augmenting feature-based voice data to traina speech processing system to process speech signals in a noisyenvironment. In this example, data augmentation process 10 may utilizeacoustic metadata 304, 306, 308, 310, 312, 314, 316 to disqualify 208portions of feature-based voice data 332 that do not include a speechcomponent and may utilize acoustic metadata 318, 320, 322, 324, 326,328, 330 to qualify 206 other portions of feature-based voice data 332for training and/or adapting the speech processing system.

While examples have been provided for qualifying and disqualifyingportions of feature-based voice data 332 for training purposes, it willbe appreciated that data augmentation process 10 may utilize acousticmetadata to qualify and/or disqualify portions of feature-based voicedata for other purposes within the scope of the present disclosure.

Gain-Based Augmentations of Feature-Based Voice Data

Referring also to FIG. 4 and in some implementations, data augmentationprocess 10 may receive 400 feature-based voice data associated with afirst acoustic domain. One or more gain-based augmentations may beperformed 402 on at least a portion of the feature-based voice data,thus defining gain-augmented feature-based voice data. As will bediscussed in greater detail below, a gain-based augmentation maygenerally include any change to a gain-based or gain-related property ofthe feature-based voice data. As is known in the art, gain may generallyinclude a measurement of the amplification or attenuation of a signal.

In some implementations, data augmentation process 10 may receive 400feature-based voice data associated with a first acoustic domain. Asdiscussed above and in some implementations, feature-based voice datamay be generated by converting a signal or at least a portion of asignal to the feature domain. Referring again to the example of FIG. 3and in some implementations, data augmentation process 10 may receive200 an audio signal (e.g., audio signal 300) and convert 202 the audiosignal from the time domain to the feature domain to generatefeature-based voice data (e.g., feature-based voice data 332) associatedwith the audio signal (e.g., audio signal 300). While an example hasbeen provided of converting a signal from the time domain to the featuredomain, it will be appreciated that a signal may be converted to thefeature domain from any domain, within the scope of the presentdisclosure.

In some implementations, the feature-based voice data may be associatedwith a first acoustic domain. An acoustic domain may generally includethe factors and characteristics that define the quality of a signal. Forexample, suppose a speaker is speaking into a receiver on a telephone inan enclosed office. In this example, the acoustic domain is defined bythe receiving microphone in the telephone (i.e., signal processingcharacteristics of the microphone), the rate at which the speakerspeaks, any noise within the enclosed office, the reverberationexperienced within the enclosed office, etc. Now suppose the speakerswitches to a speakerphone receiver on the telephone. In this example,while the environmental features remain the same (i.e., the enclosedoffice), the acoustic domain has changed because the speakerphonereceiver represents different factors and characteristics that mayimpact the signal processing differently than the receiver on thetelephone. In some implementations, the change in acoustic domain mayhave various impacts on the performance of a speech processing system.Accordingly, data augmentation process 10 may allow feature-based voicedata from one acoustic domain to be used in the training of speechprocessing systems in other acoustic domains and/or for adapting aspeech processing system or model with new adaptation data.

In some implementations, data augmentation process 10 may perform 402one or more gain-based augmentations on at least a portion of thefeature-based voice data, thus defining gain-augmented feature-basedvoice data. Referring also to the example of FIG. 5 and in someimplementations, data augmentation process 10 may receive 400feature-based voice data (e.g., feature-based voice data 500) associatedwith a first acoustic domain. In the example of FIG. 5, feature-basedvoice data 500 may include a plurality of feature coefficients (e.g.,Mel Filter Bank coefficients, Mel-frequency cepstral coefficients, etc.)represented as a spectrogram of a signal as a function of frequency (onthe vertical axis) and time (on the horizontal axis) where the shade ofeach quadrant represents the amplitude of each feature coefficient.While one example of feature-based voice data has been described, itwill be appreciated that the feature-based voice data may be representedin various ways within the scope of the present disclosure.

In this example, data augmentation process 10 may perform 402 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data associated with the first acoustic domain. As will bediscussed in greater detail below, it may be desirable to augment atleast a portion of feature-based voice data associated with a particularacoustic domain for various reasons. For example and in someimplementations, data augmentation process 10 may perform 402 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data to utilize the feature-based voice data for training a speechprocessing system in a target acoustic domain. In this example, dataaugmentation process 10 may train a speech processing system withfeature-based voice data from a different acoustic domain which mayallow for speech processing systems to be effectively utilized invarious acoustic domains using an augmented set of trainingfeature-based voice data.

In another example, data augmentation process 10 may perform 402 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data to generate additional training data for speech processingsystems with varying levels of gain. In this manner, data augmentationprocess 10 may train speech processing systems to be more robust againstvariations in gain by augmenting a set of training feature-based voicedata with various gain levels. While two examples have been provided forutilizing gain-augmented feature-based voice data, it will beappreciated that data augmentation process 10 may perform 402 gain-basedaugmentations on feature-based voice data for various other purposeswithin the scope of the present disclosure. For example and in someimplementations, gain-based augmentations may be used to adapt a speechprocessing system with new adaptation data (e.g., gain-basedaugmentations).

As discussed above, after a signal is converted to the feature domain,it may be impossible to determine certain acoustic properties of thesignal without converting the signal back to the time domain. In someimplementations, when receiving 400 the feature-based voice data, dataaugmentation process 10 may also receive information associated with thefeature-based voice data from an external source (e.g., a userinterface, a database, etc.). In some implementations, the informationassociated with the feature-based voice data may include informationabout the feature-based voice data generally. For example, theinformation may identify the feature-based voice data as being recordedin a general acoustic domain (e.g., vehicle noises). In someimplementations, the information associated with the feature-based voicedata may or may not be specific to the feature-based voice data. Forexample, the information may provide general characteristics associatedwith the feature-based voice data (e.g., signals with vehicle noisetypically have a particular gain level distribution).

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include performing 210 one or more gain-based augmentationson at least a portion of the feature-based voice data associated withthe signal based upon, at least in part, the acoustic metadata. Asdiscussed above, data augmentation process 10 may extract 200 acousticmetadata from a signal before the signal is converted 204 to the featuredomain. As discussed above, the extracted acoustic metadata may includeglobal acoustic metadata associated with the signal generally and/oracoustic metadata associated with or specific to particular portions ofthe signal. In this manner, the extracted acoustic metadata may providemore specific information about the acoustic domain of the feature-basedvoice data than available from other more generalized information aboutthe feature-based voice data. As will be discussed in greater detailbelow and in some implementations, acoustic metadata associated with asignal may allow data augmentation process 10 to determine variouscharacteristics of the feature-based voice data and perform 402 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata.

In some implementations, data augmentation process 10 may receive 404 aselection of a target acoustic domain. A target acoustic domain mayinclude a target set of factors and characteristics that define thequality of a signal. In some implementations, data augmentation process10 may receive 404 a selection of a target acoustic domain by providingparticular gain-based characteristics associated with the targetacoustic domain. In some implementations, data augmentation process 10may utilize a graphical user interface for receiving 404 a selection ofa target acoustic domain from a library of predefined acoustic domains.In one example, data augmentations process 10 may receive selections(e.g., via a graphical user interface) of various characteristics of theacoustic domain (e.g., a selection of the reverberation, signal-to-noiseratio (SNR), a type of microphone array, a particular noise track, etc.)to define a target acoustic domain. As will be discussed in greaterdetail below and in some implementations, data augmentation process 10may receive a range or distribution of characteristics for the targetacoustic domain. While an example of a graphical user interface has beendescribed, it will be appreciated that a target acoustic domain may beselected in various ways within the scope of the present disclosure(e.g., manually by a user, automatically by data augmentation process10, a pre-defined target acoustic domain, etc.).

Referring also to the example of FIG. 6 and in some implementations,suppose a speech processing system is trained for processing data in aparticular acoustic domain (e.g., processing speech (e.g., speech signal600) in a laboratory where the speaker (e.g., speaker 602) is speakingdirectly into a microphone (e.g., microphone array 604 of microphoneelements 606, 608, 610)). In this example, because speaker 602 isspeaking directly into microphone 604, the feature-based voice data ortraining feature-based voice data associated with speech signal 600 mayhave little attenuation (i.e., a high signal amplitude). However,suppose that speaker 602's head turns one way or another while speaking.In this example, the higher frequency signal components (e.g.,represented by beampattern 612) of speech signal 600 may be moreattenuated relative to the lower frequency signal components (e.g.,represented by beampattern 614). In this example, movement of thespeaker's head may introduce spectral variations to the signal that mayimpact the operation of a speech processing system trained withfeature-based voice data associated with speaker 602 speaking directlyinto microphone array 604. In this example, data augmentation process 10may receive 404 a selection of the acoustic domain associated with thespeaker's head moving as the target acoustic domain. While an example ofa particular target acoustic domain has been provided, it will beappreciated that various target acoustic domains may be selected withinthe scope of the present disclosure.

In some implementations, performing 402 the one or more gain-basedaugmentations to the at least a portion of the feature-based voice datamay include performing 406 the one or more gain-based augmentations tothe at least a portion of the feature-based voice data based upon, atleast in part, the target acoustic domain. Returning to the aboveexample, suppose data augmentation process 10 receives 404 a selectionof the acoustic domain associated with a speaker's head moving whilespeaking in a laboratory. In this example, data augmentation process 10may perform 406 one or more gain-based augmentations on at least aportion of the feature-based voice data of the first acoustic domain(e.g., the acoustic domain associated with a speaker speaking directlyinto a microphone within a laboratory (e.g., as shown in FIG. 6)).

In some implementations, data augmentation process 10 may perform 406one or more gain-based augmentations on at least a portion offeature-based voice data 500 to account for a speaker's head movementswhile speaking. Accordingly, data augmentation process 10 may perform406 these gain-based augmentations to map feature-based voice data 500from the first acoustic domain (e.g., the acoustic domain associatedwith a speaker speaking directly into a microphone within a laboratory)to a target acoustic domain (e.g., the acoustic domain associated with aspeaker's head turning while speaking within the laboratory). In thismanner, a speech processing system may be trained using feature-basedvoice data augmented from one acoustic domain for processing speech inanother acoustic domain.

As discussed above and in some implementations, performing 210 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata. For example, data augmentation process 10 may extract200 acoustic metadata (e.g., acoustic metadata 502) associated withfeature-based voice data 500. As discussed above, acoustic metadata 502may allow data augmentation process 10 to determine variouscharacteristics of the feature-based voice data and perform 402 one ormore gain-based augmentations on at least a portion of the feature-basedvoice data associated with the signal.

In some implementations, data augmentation process 10 may determine 408a distribution of gain levels associated with the target acousticdomain. For example and in some implementations, when performing 406 theone or more gain-based augmentations on feature-based voice dataassociated with a first acoustic domain for use in a target acousticdomain, the target acoustic domain may not have a consistent gain levelor range of gain levels. In this example, data augmentation process 10may determine 408 a distribution of gain levels associated with thetarget acoustic domain. For example, data augmentation process 10 mayprocess training data (e.g., time domain data and/or feature-based voicedata) from the target acoustic domain to determine a distribution ofgain levels. In some implementations, determining 408 the distributionof gain levels from training data associated with the target acousticdomain may include determining how the gain of the training data variesover time for particular frequencies or frequency bands. In this manner,data augmentation process 10 may determine 408 a distribution of gainlevels to apply when performing gain-based augmentations on thefeature-based voice data associated with the first acoustic domain.

In some implementations, performing 402 the one or more gain-basedaugmentations to the at least a portion of the feature-based voice datamay include performing 410 the one or more gain-based augmentations tothe at least a portion of the feature-based voice data based upon, atleast in part, the distribution of gain levels associated with thetarget acoustic domain. As discussed above, with a distribution of gainlevels associated with the target acoustic domain, data augmentationprocess 10 may perform 410 one or more gain-based augmentations on atleast a portion of the feature-based voice data to include a similardistribution of gain levels as the target acoustic domain.

Returning to the examples of FIGS. 5-6 and in some implementations,suppose data augmentation process 10 determines 408 a distribution ofgain levels (e.g., distribution of gain levels 504) associated with thetarget acoustic domain (e.g., the acoustic domain associated with aspeaker's head turning while speaking within a laboratory). In thisexample, data augmentation process 10 may perform 410 one or moregain-based augmentations on the feature-based voice data (e.g.,feature-based voice data 500) associated with the first acoustic domain(e.g., the acoustic domain associated with a speaker speaking directlyinto a microphone within a laboratory) to include a similar or the samedistribution of gain levels as in the target acoustic domain (e.g., theacoustic domain associated with a speaker's head turning while speakingwithin a laboratory).

As will be discussed in greater detail below, data augmentation process10 may perform 410 gain-based augmentations on feature-based voice data500 by amplifying and/or attenuating certain portions (e.g., particularfrequencies, frequency bands, etc.) of feature-based voice data 500based upon, at least in part, the distribution of gain levels associatedwith the target domain. In this manner, data augmentation process 10 mayallow feature-based voice data 500 associated with one acoustic domain(e.g., the acoustic domain associated with a speaker speaking directlyinto a microphone within a laboratory) to be used to train speechprocessing systems in a target acoustic domain (e.g., the acousticdomain associated with a speaker's head turning while speaking within alaboratory), thus defining gain-augmented feature-based voice data(e.g., gain-augmented feature-based voice data 506).

While an example of performing 410 one or more gain-based augmentationson at least a portion of feature-based voice data has been described foraugmenting feature-based voice data to include a similar distribution ofgain levels as that of a target acoustic domain, it will be appreciatedthat data augmentation process 10 may perform 402 one or more gain-basedaugmentations on at least a portion of feature-based voice data forother purposes within the scope of the present disclosure. As discussedabove, data augmentation may allow an existing set of training data tobe used in other acoustic domains or to provide more diverse trainingdata within the same acoustic domain. For example, suppose that a speechprocessing system is trained with training data having a particular gainlevel and/or limited range of gain levels. If a speech processing systemis exposed to speech signals with gain levels that vary from thetraining data, the speech processing system may be less effective inprocessing the speech signal. In this manner, data augmentation process10 may perform 402 one or more gain-based augmentations on at least aportion of the feature-based voice data to generate more diverse (e.g.,with varying gain levels) training data for a speech processing system.

In some implementations, performing 402 the one or more gain-basedaugmentations to the at least a portion of the feature-based voice datamay include amplifying 412 at least a portion of the feature-based voicedata. For example and in some implementations, data augmentation process10 may determine that at least a portion of the feature-based voice dataneeds to be amplified. In one example and as discussed above, dataaugmentation process 10 may receive 404 a selection of a target acousticdomain (e.g., an acoustic domain associated with a speaker speakingdirectly into a microphone within a laboratory) and may determine thatone or more portions of the feature-based voice data (e.g.,feature-based voice data 500) need additional gain to be used astraining data in the target acoustic domain. For example and asdiscussed above, data augmentation process 10 may determine 408 adistribution of gain levels associated with the target domain toidentify specific portions of feature-based voice data 500 to amplify.In this example, data augmentation process 10 may amplify 412 at least aportion of feature-based voice data 500 based upon, at least in part,the target acoustic domain (e.g., the acoustic domain associated with aspeaker speaking directly into a microphone within a laboratory).

In another example, suppose that training data for a particular acousticdomain has a limited range of gain levels. In this example, dataaugmentation process 10 may identify particular portions offeature-based voice data 500 to amplify 412. For example, dataaugmentation process 10 may amplify 412 various portions offeature-based voice data 500 with lower gain levels than the existingtraining data to generate more diverse training data.

In some implementations, amplifying 412 at least a portion of thefeature-based voice data may include amplifying portions of thefeature-based voice data based upon, at least in part, the frequency orfrequency bands of the feature-based voice data. For example, dataaugmentation process 10 may amplify 412 at least a portion of thefeature-based voice data with a particular frequency or frequency band.In one example and as discussed above, suppose a selected targetacoustic domain is determined to have a particular gain or distributionof gain levels. In this example, data augmentation process 10 mayidentify a particular frequency or frequency bands within feature-basedvoice data 500 that e.g., fall below the particular gain or distributionof gain levels. Data augmentation process 10 may amplify 412 the portionor portions of feature-based voice data 500 that correspond to theidentified frequency or frequency bands. In this manner, dataaugmentation process 10 may perform 402 gain-based augmentations on atleast a portion of the feature-based voice data based upon, at least inpart, the frequency or frequency band of the at least a portion of thefeature-based voice data.

In another example, suppose that training data for a particular acousticdomain has a limited range of gain levels at a particular frequency orfrequency band. In this example, data augmentation process 10 mayidentify the portions of feature-based voice data 500 corresponding tothese frequencies or frequency bands to amplify 412. For example, dataaugmentation process 10 may amplify 412 various portions offeature-based voice data 500 corresponding to particular frequencies orfrequency bands with lower gain levels than the existing training datato generate more diverse training data.

In some implementations, performing 402 the one or more gain-basedaugmentations to the at least a portion of the feature-based voice datamay include attenuating 414 at least a portion of the feature-basedvoice data. For example and in some implementations, data augmentationprocess 10 may determine that at least a portion of the feature-basedvoice data needs to be attenuated. In one example and as discussedabove, data augmentation process 10 may receive 404 a selection of atarget acoustic domain (e.g., acoustic domain associated with aspeaker's head turning while speaking within a laboratory) and maydetermine that one or more portions of the feature-based voice data(e.g., feature-based voice data 500) need to be attenuated to be used astraining data in the target acoustic domain. For example and asdiscussed above, data augmentation process 10 may determine 408 adistribution of gain levels associated with the target domain toidentify specific portions of feature-based voice data 500 to attenuate414. In this example, data augmentation process 10 may attenuate 414 atleast a portion of feature-based voice data 500 based upon, at least inpart, the target acoustic domain (e.g., the acoustic domain associatedwith a speaker's head turning while speaking within a laboratory).

In another example, suppose that training data for a particular acousticdomain has a limited range of gain levels. In this example, dataaugmentation process 10 may identify particular portions offeature-based voice data 500 to attenuate 414. For example, dataaugmentation process 10 may attenuate 414 various portions offeature-based voice data 500 with higher gain levels than the existingtraining data to generate more diverse training data.

In some implementations, attenuating 414 at least a portion of thefeature-based voice data may include attenuating portions of thefeature-based voice data based upon, at least in part, the frequency orfrequency bands of the feature-based voice data. For example, dataaugmentation process 10 may attenuate 414 at least a portion of thefeature-based voice data with a particular frequency or frequency band.In one example and as discussed above, suppose a selected targetacoustic domain is determined to have a particular gain or distributionof gain levels. In this example, data augmentation process 10 mayidentify a particular frequency or frequency bands within feature-basedvoice data 500 that e.g., are above the particular gain or distributionof gain levels. Data augmentation process 10 may attenuate the portionor portions of feature-based voice data 500 that correspond to theidentified frequency or frequency bands. In this manner, dataaugmentation process 10 may perform gain-based augmentations on at leasta portion of the feature-based voice data based upon, at least in part,the frequency or frequency band of the at least a portion of thefeature-based voice data.

In another example, suppose that training data for a particular acousticdomain has a limited range of gain levels at a particular frequency orfrequency band. In this example, data augmentation process 10 mayidentify the portions of feature-based voice data 500 corresponding tothese frequencies or frequency bands to attenuate 414. For example, dataaugmentation process 10 may attenuate 414 various portions offeature-based voice data 500 corresponding to particular frequencies orfrequency bands with higher gain levels than the existing training data.In this manner, data augmentation process 10 may generate diversetraining data by attenuating particular frequencies or frequency bandsof feature-based voice data (e.g., gain-augmented feature-based voicedata 506).

In some implementations, when performing 402 the one or more gain-basedaugmentations to the at least a portion of the feature-based voice datato generate more diverse training data, data augmentation process 10 mayapply a random gain factor to each portion (e.g., each Mel Filter Bankor other feature domain portion). In some implementations, the randomgain factor may be predefined and/or determined based upon, at least inpart, a target signal-to-noise ratio (SNR) for feature-based voice data.For example, data augmentation process 10 may amplify 412 and/orattenuate 414 various portions of feature-based voice data 500 withrandomly determined and/or predefined gain factors. In someimplementations, data augmentation process 10 may determine the range ofgain factors to be applied based upon, at least in part, a target SNR ofa target acoustic domain.

Rate-Based Augmentations of Feature-Based Voice Data

Referring also to FIG. 7 and in some implementations, data augmentationprocess 10 may receive 700 feature-based voice data associated with afirst acoustic domain. One or more rate-based augmentations may beperformed 702 on at least a portion of the feature-based voice data,thus defining rate-based augmented feature-based voice data. As will bediscussed in greater detail below, a rate-based augmentation maygenerally include any change to a speaking rate within the feature-basedvoice data. As is known in the art, a speech rate may generally includethe rate at which a person speaks as recorded within a signal.

In some implementations, data augmentation process 10 may receive 700feature-based voice data associated with a first acoustic domain. Asdiscussed above and in some implementations, feature-based voice datamay be generated by converting a signal or at least a portion of asignal to the feature domain. Referring again to the example of FIG. 3and in some implementations, data augmentation process 10 may receive200 an audio signal (e.g., audio signal 300) and convert 204 the audiosignal from the time domain to the feature domain to generatefeature-based voice data (e.g., feature-based voice data 332) associatedwith the audio signal (e.g., audio signal 300). While an example hasbeen provided of converting a signal from the time domain to the featuredomain, it will be appreciated that a signal may be converted to thefeature domain from any domain, within the scope of the presentdisclosure.

In some implementations, data augmentation process 10 may perform 702one or more rate-based augmentations on at least a portion of thefeature-based voice data, thus defining rate-based augmentedfeature-based voice data. Referring also to the example of FIG. 8 and insome implementations, data augmentation process 10 may receive 700feature-based voice data (e.g., feature-based voice data 800) associatedwith a first acoustic domain. In the example of FIG. 8, feature-basedvoice data 800 may include a plurality of feature coefficients (e.g.,Mel Filter Bank coefficients, Mel-frequency cepstral coefficients, etc.)represented as a spectrogram of a signal as a function of frequency (onthe vertical axis) and time (on the horizontal axis) where the shade ofeach quadrant represents the amplitude of each feature coefficient.While one example of feature-based voice data has been described, itwill be appreciated that the feature-based voice data may be representedin various ways within the scope of the present disclosure.

In this example, data augmentation process 10 may perform 702 one ormore rate-based augmentations on at least a portion of the feature-basedvoice data associated with the first acoustic domain. As will bediscussed in greater detail below, it may be desirable to augment atleast a portion of feature-based voice data associated with a particularacoustic domain for various reasons. For example and in someimplementations, data augmentation process 10 may perform 702 one ormore rate-based augmentations on at least a portion of the feature-basedvoice data to utilize the feature-based voice data for training a speechprocessing system in a target acoustic domain. In this example, dataaugmentation process 10 may train a speech processing system withfeature-based voice data from a different acoustic domain which mayallow for speech processing systems to be effectively utilized invarious acoustic domains using an augmented set of trainingfeature-based voice data.

In another example, data augmentation process 10 may perform 702 one ormore rate-based augmentations on at least a portion of the feature-basedvoice data to generate additional training data for speech processingsystems with varying speaking rates. In this manner, data augmentationprocess 10 may train speech processing systems to be more robust againstvariations in speaking rates by augmenting a set of trainingfeature-based voice data with various speaking rates. While two exampleshave been provided for utilizing rate-based augmented feature-basedvoice data, it will be appreciated that data augmentation process 10 mayperform rate-based augmentations on feature-based voice data for variousother purposes within the scope of the present disclosure. For exampleand in some implementations, rate-based augmentations may be used toadapt a speech processing system with new adaptation data (e.g.,rate-based augmentations).

As discussed above, after a signal is converted to the feature domain,it may be impossible to determine certain acoustic properties of thesignal without converting the signal back to the time domain. In someimplementations, when receiving 700 the feature-based voice data, dataaugmentation process 10 may also receive information associated with thefeature-based voice data. In some implementations, the informationassociated with the feature-based voice data may include informationabout the feature-based voice data generally. For example, theinformation may identify the feature-based voice data as being recordedin a general acoustic domain (e.g., feature-based voice data convertedfrom signals with typical conversation-based speaking rates). In someimplementations, the information associated with the feature-based voicedata may or may not be specific to the feature-based voice data. Forexample, the information may provide general characteristics associatedwith the feature-based voice data.

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include performing 212 one or more rate-based augmentationson at least a portion of the feature-based voice data associated withthe signal based upon, at least in part, the acoustic metadata. Asdiscussed above, data augmentation process 10 may extract 200 acousticmetadata (e.g., acoustic metadata 802) from the signal before the signalis converted 202 to the feature domain. As discussed above, theextracted acoustic metadata may include global acoustic metadataassociated with a signal generally and/or acoustic metadata associatedwith, or specific to, particular portions of the signal. In this manner,the extracted acoustic metadata may provide more specific informationabout the acoustic domain of the feature-based voice data than availablefrom other more generalized information about the feature-based voicedata. As will be discussed in greater detail below and in someimplementations, the acoustic metadata (e.g., acoustic metadata 802)associated with a signal may allow data augmentation process 10 todetermine various characteristics of the feature-based voice data andperform 212 one or more rate-based augmentations on at least a portionof the feature-based voice data associated with the signal based upon,at least in part, the acoustic domain of the feature-based voice data.

In some implementations, data augmentation process 10 may receive 704 aselection of a target acoustic domain. As discussed above, a targetacoustic domain may generally include a target set of factors andcharacteristics that define the quality of a signal. In someimplementations, data augmentation process 10 may receive 704 aselection of a target acoustic domain by providing particular speakingrate characteristics associated with the target acoustic domain. In someimplementations and as discussed above, data augmentation process 10 mayutilize a graphical user interface for receiving 704 a selection of atarget acoustic domain from a library of predefined acoustic domains. Inone example, data augmentations process 10 may receive selections (e.g.,via a graphical user interface) of various characteristics of theacoustic domain (e.g., a selection of the reverberation, signal-to-noiseratio (SNR), a type of microphone array, a particular noise track, etc.)to define a target acoustic domain. As will be discussed in greaterdetail below and in some implementations, data augmentation process 10may receive a range or distribution of characteristics for the targetacoustic domain.

In one example, suppose a speech processing system is trained forprocessing speech in a particular acoustic domain (e.g., a speakerspeaking into a microphone dictation system configured to recognize andtranscribe speech). In this example, because the speaker is speakingdirectly into a microphone to dictate speech, the speaker's speakingrate and annunciation may be very clear and the feature-based voice datamay have a particular speaking rate or limited range of speaking rates.

However, other acoustic domains may receive and process speech withdifferent speaking rates or changes in speaking rates. For example,suppose a microphone is deployed in a medical environment and isconfigured to record and process conversations between a medicalprofessional and a patient. In this example, the speaking rate of amedical professional may be distinct from that of a speaker using adictation system and the speaking rate of the medical professional andthe patient may be distinct. Data augmentation process 10 may receive704 a selection of the acoustic domain associated with a medicalprofessional's office including a microphone array configured to processconversations between medical professionals and patients. While anexample of a particular target acoustic domain has been provided, itwill be appreciated that various target acoustic domains may be selectedwithin the scope of the present disclosure.

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice datamay include performing 706 the one or more rate-based augmentations tothe at least a portion of the feature-based voice data based upon, atleast in part, the target acoustic domain. Returning to the aboveexample, suppose data augmentation process 10 receives 704 a selectionof the acoustic domain associated with a medical professional's officeincluding a microphone array configured to process conversations betweenmedical professionals and patients. In this example, data augmentationprocess 10 may perform 706 one or more rate-based augmentations on atleast a portion of the feature-based voice data of the first acousticdomain (e.g., the acoustic domain associated with a speaker speakinginto a microphone dictation system configured to recognize andtranscribe speech).

In some implementations, data augmentation process 10 may perform 706one or more rate-based augmentations on at least a portion offeature-based voice data 800 to account for the variations in speakingrates. Accordingly, data augmentation process 10 may perform 706rate-based augmentations to map feature-based voice data 800 from thefirst acoustic domain (e.g., the acoustic domain associated with aspeaker speaking into a microphone dictation system) to a targetacoustic domain (e.g., the acoustic domain associated with a medicalprofessional's office including a microphone array configured to processconversations between medical professionals and patients). In thismanner, a speech processing system may be trained using feature-basedvoice data from one acoustic domain for processing speech in anotheracoustic domain.

In some implementations, data augmentation process 10 may determine adistribution of speaking rates and changes in speaking rates associatedwith the target acoustic domain. For example and in someimplementations, when performing 706 the one or more rate-basedaugmentations on feature-based voice data associated with a firstacoustic domain for use in a target acoustic domain, the target acousticdomain may not have a consistent speaking rate or known range ofspeaking rates. In this example, data augmentation process 10 maydetermine a distribution of speaking rates associated with the targetacoustic domain. For example, data augmentation process 10 may processtraining data (e.g., time domain data and/or feature-based voice data)from the target acoustic domain to determine a distribution of speakingrates. In some implementations, determining the distribution of speakingrates from training data associated with the target acoustic domain mayinclude determining how the rate of speaking within the training datavaries over time. In this manner, data augmentation process 10 maydetermine a distribution of speaking rates to apply when performingrate-based augmentations on the feature-based voice data associated withthe first acoustic domain.

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice datamay include performing the one or more rate-based augmentations to theat least a portion of the feature-based voice data based upon, at leastin part, the distribution of speaking rates associated with the targetacoustic domain. As discussed above, with a distribution of speakingrates associated with the target domain, data augmentation process 10may perform 702 one or more rate-based augmentations on at least aportion of the feature-based voice data to include a similardistribution of speaking rates as the target acoustic domain.

In some implementations, suppose data augmentation process 10 determinesa distribution of speaking rates (e.g., distribution of speaking rates804) associated with the target acoustic domain (e.g., the acousticdomain associated with a medical professional's office including amicrophone array configured to process conversations between medicalprofessionals and patients). In this example, data augmentation process10 may perform one or more rate-based augmentations on the feature-basedvoice data (e.g., feature-based voice data 800) associated with thefirst acoustic domain (e.g., the acoustic domain associated with aspeaker speaking into a microphone dictation system configured torecognize and transcribe speech) to include a similar or the samedistribution of speaking rates as in the target acoustic domain.

As will be discussed in greater detail below, data augmentation process10 may perform rate-based augmentations on feature-based voice data 800by adding and/or dropping certain portions (e.g., frames within thefeature domain and/or frequency domain) of feature-based voice data 800based upon, at least in part, the distribution of speaking ratesassociated with the target domain. In this manner, data augmentationprocess 10 may allow feature-based voice data 800 associated with oneacoustic domain (e.g., the acoustic domain associated with a speakerspeaking into a microphone dictation system) to be used to train speechprocessing systems in a target acoustic domain (e.g., the acousticdomain associated with a medical professional's office including amicrophone array configured to process conversations between medicalprofessionals and patients), thus defining rate-based augmentedfeature-based voice data (e.g., rate-based augmented feature-based voicedata 806).

While an example of performing 706 one or more rate-based augmentationson at least a portion of feature-based voice data has been described foraugmenting feature-based voice data to include a similar distribution ofspeaking rates as that of a target acoustic domain, it will beappreciated that data augmentation process 10 may perform 702 one ormore rate-based augmentations on at least a portion of feature-basedvoice data for other purposes within the scope of the presentdisclosure. As discussed above, data augmentation may allow an existingset of training data to be used in other acoustic domains or to providemore diverse training data within the same acoustic domain. For example,suppose that a speech processing system is trained with training datahaving a particular speaking rate and/or limited range of speakingrates. If a speech processing system is exposed to speech signals withspeaking rates that vary from the training data, the speech processingsystem may be less effective in processing the speech signals. In thismanner, data augmentation process 10 may perform 702 one or morerate-based augmentations on at least a portion of the feature-basedvoice data to generate more diverse (e.g., with varying speaking rates)training data for a speech processing system.

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice datamay include decreasing 708 a phoneme-rate of at least a portion of thefeature-based voice data. As is known in the art, a phoneme maygenerally include small and perceptually distinct units of sound in alanguage used to distinguish one word from another word and aphoneme-rate may generally include the number of phonemes per some unitof time. For example and in some implementations, data augmentationprocess 10 may determine a phoneme-rate of at least a portion of thefeature-based voice data (e.g., from acoustic metadata 802 and/or fromgeneral information associated with feature-based voice data 800). Insome implementations, data augmentation process 10 may decrease 708 aphoneme-rate of at least a portion of the feature-based voice data toutilize the feature-based voice data for a target acoustic domain and/orto generate additional training data with varying phoneme-rates.

In some implementations, decreasing 708 a phoneme-rate of at least aportion of the feature-based voice data may include adding 710 one ormore frames to the feature-based voice data. For example, suppose thatfeature-based voice data 800 is associated with a first acoustic domain(e.g., an acoustic domain associated with a medical professional'soffice including a microphone array configured to process conversationsbetween medical professionals and patients). Suppose that dataaugmentation process 10 receives 704 a selection of a target acousticdomain (e.g., the acoustic domain associated with a speaker speakinginto a microphone of a dictation system configured to recognize andtranscribe speech). In this example, because a speaker (e.g., a patientand/or a medical professional) is speaking more quickly than whenspeaking into the microphone of a dictation system, the phoneme-rate mayof feature-based voice data 800 may be too fast for processing by adictation system. Accordingly, data augmentation process 10 maydetermine a phoneme-rate and/or a distribution of phoneme ratesassociated with the target acoustic domain (e.g., the acoustic domainassociated with a speaker speaking into a microphone of a dictationsystem) and a phoneme rate and/or a distribution of phoneme rates offeature-based voice data 800 (e.g., the acoustic domain associated witha medical professional's office including a microphone array configuredto process conversations between medical professionals and patients).

In this example, suppose data augmentation process 10 determines thatthe phoneme-rate and/or distribution of phoneme rates of feature-basedvoice data 800 is higher than that of target acoustic domain. Dataaugmentation process 10 may decrease 708 the phoneme-rate offeature-based voice data 800 by adding 710 one or more frames tofeature-based voice data 800. In some implementations, the one or moreframes may include frame of frequencies and/or bands of frequencies. Forexample, data augmentation process 10 may add 710 one or more frames orportions without a phoneme and/or with the same phoneme as a previousframe or portion of feature-based voice data 800. In this manner, dataaugmentation process 10 may decrease 708 the phoneme-rate offeature-based voice data based upon, at least in part, the phoneme-rateof the target acoustic domain.

While the above example of decreasing 708 a phoneme-rate of a least aportion of feature-based voice data includes decreasing 708 thephoneme-rate of the at least a portion of the feature-based voice databased upon, at least in part, the phoneme rate and/or distribution ofphoneme-rates of a target acoustic domain, it will be appreciated thatdata augmentation process 10 may decrease 708 the phoneme-rate of the atleast a portion of the feature-based voice data for other purposes(e.g., to generate more diverse training data with varyingphoneme-rates, etc.).

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice datamay include increasing 712 a phoneme-rate of at least a portion of thefeature-based voice data. As discussed above and in someimplementations, data augmentation process 10 may determine aphoneme-rate of at least a portion of the feature-based voice data(e.g., from acoustic metadata 802 and/or from general informationassociated with feature-based voice data 800). In some implementations,data augmentation process 10 may increase 712 a phoneme-rate of at leasta portion of the feature-based voice data to utilize the feature-basedvoice data for a target acoustic domain and/or to generate additionaltraining data with varying phoneme-rates.

In some implementations, increasing 712 a phoneme-rate of at least aportion of the feature-based voice data may include dropping 714 one ormore frames from the feature-based voice data. For example, suppose thatfeature-based voice data 800 is associated with a first acoustic domain(e.g., an acoustic domain associated with a speaker speaking into amicrophone of a dictation system). Suppose that data augmentationprocess 10 receives a selection of a target acoustic domain (e.g., anacoustic domain associated with a medical professional's officeincluding a microphone array configured to process conversations betweenmedical professionals and patients). In this example, because a speakerspeaking into the microphone of a dictation system speaks more slowlythan the speakers (e.g., patients and/or medical professionals) do in aconversation, the phoneme-rate may of feature-based voice data 800 maybe too slow for processing by speech processing system trained withconversational data. Accordingly, data augmentation process 10 maydetermine a phoneme-rate and/or a distribution of phoneme ratesassociated with the target acoustic domain (e.g., the acoustic domainassociated with a medical professional's office including a microphonearray configured to process conversations between medical professionalsand patients) and a phoneme rate and/or a distribution of phoneme ratesof feature-based voice data 800 (e.g., the acoustic domain associatedwith a speaker speaking into a microphone of a dictation system).

In this example, suppose that data augmentation process 10 determinesthat the phoneme-rate and/or distribution of phoneme rates offeature-based voice data 800 is lower than that of the target acousticdomain. Data augmentation process 10 may increase 712 the phoneme-rateof feature-based voice data 800 by dropping 714 one or more frames fromfeature-based voice data 800. In some implementations, the one or moreframes may include a frequency and/or bands of frequencies. For example,data augmentation process 10 may drop 714 one or more frames or portionswithout a phoneme and/or with the same phoneme as a previous frame orportion of feature-based voice data 800. In this manner, dataaugmentation process 10 may increase 712 the phoneme-rate offeature-based voice data based upon, at least in part, the phoneme-rateof the target acoustic domain.

While the above example of increasing 712 a phoneme-rate of a least aportion of feature-based voice data includes increasing 712 thephoneme-rate of the at least a portion of the feature-based voice databased upon, at least in part, the phoneme rate and/or distribution ofphoneme-rates of a target acoustic domain, it will be appreciated thatdata augmentation process 10 may increase 712 the phoneme-rate of the atleast a portion of the feature-based voice data for other purposes(e.g., generate more diverse training data with varying phoneme-rates).

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice datamay include training a machine learning system or model (e.g., machinelearning model 72) to perform the one or more rate-based augmentations.As is known in the art, a machine learning model may generally includean algorithm or combination of algorithms that has been trained torecognize certain types of patterns. For example, machine learningapproaches may be generally divided into three categories, depending onthe nature of the signal available: supervised learning, unsupervisedlearning, and reinforcement learning. As is known in the art, supervisedlearning may include presenting a computing device with example inputsand their desired outputs, given by a “teacher”, where the goal is tolearn a general rule that maps inputs to outputs. With unsupervisedlearning, no labels are given to the learning algorithm, leaving it onits own to find structure in its input. Unsupervised learning can be agoal in itself (discovering hidden patterns in data) or a means towardsan end (feature learning). As is known in the art, reinforcementlearning may generally include a computing device interacting in adynamic environment in which it must perform a certain goal (such asdriving a vehicle or playing a game against an opponent). As itnavigates its problem space, the program is provided feedback that'sanalogous to rewards, which it tries to maximize. While three examplesof machine learning approaches have been provided, it will beappreciated that other machine learning approaches are possible withinthe scope of the present disclosure.

In some implementations, data augmentation process 10 may train 716 amachine learning model to one or more of add at least one frame to thefeature-based voice data and drop at least one frame from thefeature-based voice data based upon, at least in part, the targetacoustic domain. For example and as discussed above, data augmentationprocess 10 may train a neural network (e.g., machine learning model 72)to decrease 708 and/or increase 712 the phoneme-rate of feature-basedvoice data 800 by providing training data with various phoneme-ratesassociated with various feature-based voice data. As discussed above andin some implementations, data augmentation process 10 may providetraining data associated with a target acoustic domain to machinelearning model 72 and machine learning model 72 may determine a speakingrate associated with the target acoustic domain and/or a distribution ofspeaking rates for the target acoustic domain.

In some implementations, performing 702 the one or more rate-basedaugmentations to the at least a portion of the feature-based voice databased upon, at least in part, the target acoustic domain may includeperforming 718 the one or more rate-based augmentations to the at leasta portion of the feature-based voice data using the trained machinelearning model configured to one or more of add at least one frame tothe feature-based voice data and drop at least one frame from thefeature-based voice data based upon, at least in part, the targetacoustic domain. In this manner, the neural network may be trained toadd one or more frames to and/or drop one or more frames from thefeature-based voice data with the input of a target acoustic domainand/or a selection to generate more diverse training data. While anexample of a neural network has been described, it will be appreciatedthat any artificial intelligence or machine learning system may betrained to perform the one or more rate-based augmentations within thescope of the present disclosure. Accordingly, data augmentation process10 may train a neural network (e.g., machine learning model 72) toachieve particular rate changes directly in the feature domain.

In some implementations, data augmentation process 10 may performsmoothing 720 and/or interpolation when adding frames to and/or droppingframes from feature-based voice data 800 using machine learning model72. For example, data augmentation process 10 may smoothen the frametransitions (e.g., in the frequency domain) when adding frames and/ordropping frames. In some implementations, data augmentation process 10may determine, in response to adding and/or dropping frames fromfeature-based voice data 800, whether rate-based augmented feature-basedvoice data 806 is sufficiently smooth (e.g., based upon, a thresholdsmoothness, a threshold rate-change gradient, etc.). Accordingly,trained machine learning model 72 may be configured to ensure thatframes are “intelligently” added to and/or dropped from rate-basedaugmented feature-based voice data 806. For example, data augmentationprocess 10 may, via machine learning model 72, may apply aninterpolation of feature-based coefficients of rate-based augmentfeature-based voice data 806 to smooth 720 transitions.

Audio Feature-Based Augmentations of Feature-Based Voice Data

Referring also to FIG. 9 and in some implementations, data augmentationprocess 10 may receive 900 feature-based voice data associated with afirst acoustic domain. One or more audio feature-based augmentations maybe performed 902 on at least a portion of the feature-based voice data.Performing the one or more audio feature-based augmentations may includeadding 904 one or more audio features to the at least a portion of thefeature-based voice data and/or removing 906 one or more audio featuresfrom the at least a portion of the feature-based voice data. As will bediscussed in greater detail below, an audio feature-based augmentationmay generally include the supplementation of any audio feature orcomponent to feature-based voice data. For example, data augmentationprocess 10 may add one or more audio features to feature-based voicedata and/or may remove one or more audio features to the feature-basedvoice data.

As will be discussed in greater detail below, audio features maygenerally include noise components, speech components, or othercomponents that may be recorded or captured in feature-based voice data.Referring again to the example of FIG. 3 and in some implementations, anaudio signal (e.g., audio signal 300) may include various components(e.g., noise components, speech components, etc.). As discussed above,when converting to the feature domain, these components may berepresented in the feature-based voice data. However, conventionaltechniques for data augmentation require the audio signal to beaugmented while in the time domain. In some implementations and as willbe discussed in greater detail below, data augmentation process 10 mayperform one or more audio feature-based augmentations on at least aportion of feature-based voice data by adding and/or removing one ormore audio features in the feature domain to or from the feature-basedvoice data.

In some implementations, data augmentation process 10 may receive 900feature-based voice data associated with a first acoustic domain. Asdiscussed above and in some implementations, feature-based voice datamay be generated by converting 904 a signal or at least a portion of asignal to the feature domain. Referring again to the example of FIG. 3and in some implementations, data augmentation process 10 may receive900 an audio signal (e.g., audio signal 300) and convert 904 the audiosignal from the time domain to the feature domain to generatefeature-based voice data (e.g., feature-based voice data 332) associatedwith the audio signal (e.g., audio signal 300). While an example hasbeen provided of converting a signal from the time domain to the featuredomain, it will be appreciated that a signal may be converted to thefeature domain from any domain, within the scope of the presentdisclosure.

In some implementations, data augmentation process 10 may perform 902one or more audio feature-based augmentations on at least a portion ofthe feature-based voice data. Referring also to the example of FIG. 10and in some implementations, data augmentation process 10 may receive900 feature-based voice data (e.g., feature-based voice data 1000)associated with a first acoustic domain. In the example of FIG. 10,feature-based voice data 1000 may include a plurality of featurecoefficients (e.g., Mel Filter Bank coefficients, Mel-frequency cepstralcoefficients, etc.) represented as a spectrogram of a signal as afunction of frequency (on the vertical axis) and time (on the horizontalaxis) where the shade of each quadrant represents the amplitude of eachfeature coefficient. While one example of feature-based voice data hasbeen described, it will be appreciated that the feature-based voice datamay be represented in various ways within the scope of the presentdisclosure.

In some implementations, data augmentation process 10 may perform 902one or more audio feature-based augmentations on at least a portion ofthe feature-based voice data associated with the first acoustic domain.As will be discussed in greater detail below, it may be desirable toaugment at least a portion of feature-based voice data associated with aparticular acoustic domain for various reasons. For example and in someimplementations, data augmentation process 10 may perform 902 one ormore audio feature-based augmentations on at least a portion of thefeature-based voice data to utilize the feature-based voice data fortraining a speech processing system in a target acoustic domain. In thisexample, data augmentation process 10 may train a speech processingsystem with feature-based voice data from a different acoustic domainwhich may allow for speech processing systems to be effectively utilizedin various acoustic domains using a limited set of trainingfeature-based voice data.

In another example, data augmentation process 10 may perform 902 one ormore audio feature-based augmentations on at least a portion of thefeature-based voice data to generate additional training data for speechprocessing systems with various audio features. In this manner, dataaugmentation process 10 may train speech processing systems to be morerobust against variations in audio features (e.g., noise components,speech components, etc.) by augmenting a set of training feature-basedvoice data with various audio features (e.g., noise components, speechcomponents, etc.). While two examples have been provided for utilizingaudio feature-based augmented feature-based voice data, it will beappreciated that data augmentation process 10 may perform 902 audiofeature-based augmentations on feature-based voice data for variousother purposes within the scope of the present disclosure. For exampleand in some implementations, audio feature-based augmentations may beused to adapt a speech processing system with new adaptation data (e.g.,audio feature-based augmentations).

As discussed above, after a signal is converted to the feature domain,it may be impossible to determine certain acoustic properties of thesignal without converting the signal back to the time domain. In someimplementations, when receiving 900 the feature-based voice data, dataaugmentation process 10 may also receive information associated with thefeature-based voice data. In some implementations, the informationassociated with the feature-based voice data may include informationabout the feature-based voice data generally. For example, theinformation may identify the feature-based voice data as being recordedin a general acoustic domain (e.g., vehicle noises). In someimplementations, the information associated with the feature-based voicedata may or may not be specific to the feature-based voice data. Forexample, the information may provide general characteristics associatedwith the feature-based voice data.

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include performing 214 one or more audio feature-basedaugmentations on at least a portion of the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata. As discussed above, data augmentation process 10 may extract200 acoustic metadata from the signal before the signal is converted 202to the feature domain. As discussed above, the extracted acousticmetadata may include global acoustic metadata associated with a signalgenerally and/or acoustic metadata associated with, or specific to,particular portions of the signal. In this manner, the extractedacoustic metadata may provide more specific information about theacoustic domain of the feature-based voice data than available fromother more generalized information about the feature-based voice data.As will be discussed in greater detail below and in someimplementations, the acoustic metadata (e.g. acoustic metadata 1002)associated with a signal may allow data augmentation process 10 todetermine various characteristics of the feature-based voice data andperform 214 one or more audio feature-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic domain of the feature-based voicedata.

In some implementations, data augmentation process 10 may receive 910 aselection of a target acoustic domain. As discussed above, a targetacoustic domain may generally include a target set of factors andcharacteristics that define the quality of a signal. In someimplementations, data augmentation process 10 may receive 910 aselection of a target acoustic domain by providing particular audiofeature-based characteristics associated with the target acoustic domain(e.g., presence or absence of particular noise components and/or speechcomponents). In some implementations, data augmentation process 10 mayutilize a graphical user interface for receiving 910 a selection of atarget acoustic domain from a library of predefined acoustic domains. Inone example, data augmentation process 10 may receive selections (e.g.,via a graphical user interface) of various characteristics of theacoustic domain (e.g., a selection of the reverberation, signal-to-noiseratio (SNR), a type of microphone array, a particular noise track, etc.)to define a target acoustic domain. As will be discussed in greaterdetail below and in some implementations, data augmentation process 10may receive a range or distribution of characteristics for the targetacoustic domain.

In one example, suppose a speech processing system is trained forprocessing speech in a particular acoustic domain (e.g., a speakerspeaking into a microphone of a vehicle's entertainment system). In thisexample, because the speaker is speaking into a microphone of a vehicle,there are various noise components or features that are likely to berecorded while the speaker speaks (e.g., road noise, noise from an openwindow, noise from the air conditioning system, etc.).

However, other acoustic domains may receive and process speech withdifferent audio features (or the lack thereof). For example, suppose amicrophone is deployed in a medical environment and is configured torecord and process conversations between a medical professional and apatient. In this example, the audio features of feature-based voice dataof a recorded conversation between a medical professional and a patientmay be distinct from that of a speaker speaking into the microphone of avehicle's entertainment system. In this example, data augmentationprocess 10 may receive 910 a selection of a target acoustic domain(e.g., a target acoustic domain associated with a medical professional'soffice including a microphone array configured to process conversationsbetween medical professionals and patients). While one example of aparticular target acoustic domain has been discussed above, it will beappreciated that various target acoustic domains may be selected withinthe scope of the present disclosure.

In some implementations, performing 902 the one or more audiofeature-based augmentations to the at least a portion of thefeature-based voice data may include performing 912 the one or moreaudio feature-based augmentations to the at least a portion of thefeature-based voice data based upon, at least in part, the targetacoustic domain. Returning to the above example, suppose dataaugmentation process 10 receives 910 a selection of the acoustic domainassociated with a medical professional's office including a microphonearray configured to process conversations between medical professionalsand patients, as the target acoustic domain. In this example, dataaugmentation process 10 may perform 912 one or more audio feature-basedaugmentations on at least a portion of the feature-based voice data ofthe first acoustic domain (e.g., the acoustic domain associated with aspeaker speaking into a microphone of a vehicle's entertainment system).

In some implementations, data augmentation process 10 may perform 902one or more audio feature-based augmentations on at least a portion offeature-based voice data 1000 to account for the variations in audiofeatures (e.g., noise components or features, speech components orfeatures, etc.). Accordingly, data augmentation process 10 may perform912 audio feature-based augmentations to map feature-based voice data1000 from the first acoustic domain (e.g., the acoustic domainassociated with a speaker speaking into a microphone of a vehicle'sentertainment system) to a target acoustic domain (e.g., the acousticdomain associated with a medical professional's office including amicrophone array configured to process conversations between medicalprofessionals and patients). In this manner, a speech processing systemmay be trained using feature-based voice data from one acoustic domainfor processing speech in another acoustic domain.

In some implementations, data augmentation process 10 may determine adistribution of audio features associated with the target acousticdomain. For example and in some implementations, when performing 912 theone or more audio feature-based augmentations on feature-based voicedata associated with a first acoustic domain for use in a targetacoustic domain, the target acoustic domain may not have a constantnoise feature or speech feature present in recordings captured withinthe target acoustic domain. In this example, data augmentation process10 may determine a distribution of audio features (e.g., noise features,speech features, etc.) associated with the target acoustic domain. Forexample, data augmentation process 10 may process training data (e.g.,time domain data and/or feature-based voice data) from the targetacoustic domain to determine a distribution of audio features. In someimplementations, determining the distribution of speaking rates fromtraining data associated with the target acoustic domain may includedetermining how the audio features of the training data vary over timefor particular frequencies or frequency bands (or other portions offeature-based voice data 1000). In this manner, data augmentationprocess 10 may determine a distribution of audio features to add orremove when performing audio feature-based augmentations on thefeature-based voice data associated with the first acoustic domain.

In some implementations, performing 902 the one or more audiofeature-based augmentations to the at least a portion of thefeature-based voice data may include performing the one or more audiofeature-based augmentations to the at least a portion of thefeature-based voice data based upon, at least in part, the distributionof audio features associated with the target acoustic domain. Asdiscussed above, with a distribution of audio features associated withthe target domain, data augmentation process 10 may perform 902 one ormore audio feature-based augmentations on at least a portion of thefeature-based voice data to include a similar distribution of audiofeatures as the target acoustic domain.

In one example, suppose data augmentation process 10 determines adistribution of audio features (e.g., distribution of audio features1004) associated with the target acoustic domain (e.g., the acousticdomain associated with a medical professional's office including amicrophone array configured to process conversations between medicalprofessionals and patients). In this example, data augmentation process10 may perform 912 one or more audio feature-based augmentations on thefeature-based voice data (e.g., feature-based voice data 1000)associated with the first acoustic domain (e.g., the acoustic domainassociated with a speaker speaking into a microphone of a vehicle'sentertainment system) to include a similar or the same distribution ofaudio features (e.g., noise features, speech features, etc.) as in thetarget acoustic domain.

As will be discussed in greater detail below, data augmentation process10 may perform 912 audio feature-based augmentations on feature-basedvoice data 1000 by adding 904 certain features (e.g., noise features,speech features, etc.) to and/or removing 906 certain features fromfeature-based voice data 1000 based upon, at least in part, thedistribution of audio features associated with the target domain (e.g.,distribution of audio features associated with the target domain 1004).In this manner, data augmentation process 10 may allow feature-basedvoice data 1000 associated with one acoustic domain (e.g., the acousticdomain associated with a speaker speaking into a microphone of avehicle's entertainment system) to be used to train speech processingsystems in a target acoustic domain (e.g., the acoustic domainassociated with a medical professional's office including a microphonearray configured to process conversations between medical professionalsand patients), thus defining audio feature-augmented feature-based voicedata (e.g., audio feature-augmented feature-based voice data 1006).

While an example of performing 912 one or more audio feature-basedaugmentations on at least a portion of feature-based voice data has beendescribed for augmenting feature-based voice data to include a similardistribution of audio features as that of a target acoustic domain, itwill be appreciated that data augmentation process 10 may perform one ormore audio feature-based augmentations on at least a portion offeature-based voice data for other purposes within the scope of thepresent disclosure. As discussed above, data augmentation may allow anexisting set of training data to be used in other acoustic domainsand/or to provide more diverse training data within the same acousticdomain.

For example, suppose that a speech processing system is trained withtraining data having particular audio features (e.g., speech features,audio features, etc.). If a speech processing system is exposed tospeech signals with audio features that vary from the training data, thespeech processing system may be less effective in processing the speechsignals. In this manner, data augmentation process 10 may perform 912one or more audio feature-based augmentations on at least a portion ofthe feature-based voice data to generate more diverse (e.g., varyingaudio features) training data for a speech processing system.

In some implementations, performing 902 the one or more audiofeature-based augmentations may include adding 904 one or more audiofeatures to the at least a portion of the feature-based voice data. Forexample, suppose data augmentation process 10 receives 900 feature-basedvoice data associated with a first acoustic domain (e.g., an acousticdomain (as shown in FIG. 6) associated with a speaker speaking directlyinto a microphone within a laboratory) and a selection of a targetacoustic domain (e.g., an acoustic domain associated with a speakerspeaking into a microphone of a vehicle's entertainment system). In thisexample, data augmentation process 10 may perform 902 one or more audiofeature-based augmentations on at least a portion of the feature-basedvoice data associated with the first acoustic domain (e.g.,feature-based voice data 1000). For example, data augmentation process10 may determine a distribution of audio features associated with thetarget acoustic domain and a distribution of audio features associatedwith the first acoustic domain. Data augmentation process 10 maydetermine that the target acoustic domain includes a distribution ofaudio features that are absent from the first acoustic domain (e.g.,noise features associated with road noise).

In some implementations, adding 904 the one or more audio features tothe at least a portion of the feature-based voice data may includeadding 914 one or more noise features associated with the target domainto the at least a portion of the feature-based voice data. Continuingwith the above example, suppose data augmentation process 10 determinesthat the target acoustic domain includes a distribution of audiofeatures that are absent from the first acoustic domain (e.g., noisefeatures associated with road noise). In this example, data augmentationprocess 10 may generate or access a feature domain representation of theone or more noise features. In some implementations, data augmentationprocess 10 may add 914 the one or more noise features (e.g., audiofeatures 1008) to feature-based voice data 1000, thus generating audiofeature-augmented feature-based voice data 1006. While an example ofadding a noise feature has been described, it will be appreciated thatother features (e.g., speech features, distortion features, etc.) may beadded to feature-based voice data within the scope of the presentdisclosure.

In some implementations, performing the one or more audio feature-basedaugmentations may include removing 906 one or more audio features fromthe at least a portion of the feature-based voice data. Returning to theabove example, suppose data augmentation process 10 receives 900feature-based voice data 1000 associated with a first acoustic domain(e.g., an acoustic domain associated with a speaker speaking into amicrophone of a vehicle's entertainment system) and receives 910 atarget acoustic domain (e.g., an acoustic domain associated with amedical professional's office including a microphone array configured toprocess conversations between medical professionals and patients). Inthis example, data augmentation process 10 may perform 912 one or moreaudio feature-based augmentations on at least a portion of thefeature-based voice data associated with the first acoustic domain(e.g., feature-based voice data 1000). For example, data augmentationprocess 10 may determine a distribution of audio features associatedwith the target acoustic domain and a distribution of audio featuresassociated with the first acoustic domain. In this example, dataaugmentation process 10 may determine that the first acoustic domainincludes a distribution of audio features that are absent from thetarget acoustic domain (e.g., noise features associated with roadnoise).

In some implementations, removing 906 the one or more audio features tothe at least a portion of the feature-based voice data may includeremoving 916 one or more noise features associated with the firstacoustic domain from the at least a portion of the feature-based voicedata. Continuing with the above example, suppose data augmentationprocess 10 determines that the first acoustic domain includes adistribution of audio features that are absent from the target acousticdomain (e.g., noise features associated with road noise). In someimplementations, data augmentation process 10 may remove 916 the one ormore noise features (e.g., audio features 1008) from feature-based voicedata 1000, thus generating audio feature augmented feature-based voicedata 1006. While an example of removing a noise feature has beendescribed, it will be appreciated that other features (e.g., speechfeatures, distortion features, etc.) may be removed from feature-basedvoice data within the scope of the present disclosure.

In some implementations, performing 902 the one or more audiofeature-based augmentations on at least a portion of the feature-basedvoice data may include performing 918 the one or more audiofeature-based augmentations on at least a portion of the feature-basedvoice data based upon, at least in part, a target signal-to-noise ratio(SNR). For example, when performing 902 the one or more audiofeature-based augmentations on the at least a portion of thefeature-based voice data, data augmentation process 10 may account forgain factors required to achieve a target SNR. In some implementations,data augmentation process 10 may approximate the signal level of thefeature-based voice data in the feature domain by computing the sum ofthe feature-based voice data signal (e.g., the Mel Filter Bank signal)across all time and frequency bins and dividing the sum by theapproximate time domain signal length (e.g., which may be determined bymultiplying the number of time bins in the feature-based voice datasignal by the hop size (e.g., in samples) and adding the window length(e.g., in samples)). Data augmentation process 10 may determine thesquare root of the result, giving a linear relationship to the signallevel of the time domain signal. In some implementations, dataaugmentation process 10 may adjust the signal level of feature-basedvoice data by multiplying the feature-based voice data signal by asquared factor (e.g., based upon, at least in part, comparing thecurrent SNR to the target SNR). In some implementations, if apre-emphasis filter is used when converting 904 to the feature domain(e.g., the STFT and Mel Filter Bank domain), data augmentation process10 may divide the feature-based voice data (e.g., the Mel Filter Banksignal) by the feature domain representation of the impulse response ofthat filter before summing. In this manner, data augmentation process 10may perform 918 one or more audio feature-based augmentations on atleast a portion of the feature-based voice data with a target SNR.

While several examples have been provided for performing 902 one or moreaudio feature-based augmentations on at least a portion of feature-basedvoice data, it will be appreciated that audio feature-basedaugmentations may be performed for various purposes. For example and asdiscussed above, data augmentation process 10 may perform 902 one ormore audio feature-based augmentations on at least a portion offeature-based voice data to supplement existing training data withvarious audio features (e.g., varying noise features, signal features,etc.). In some implementations, data augmentation process 10 may perform918 the one or more audio feature-based augmentations on at least aportion of the feature-based voice data based upon, at least in part, atarget signal-to-noise ratio (SNR) by applying a different gain factor(e.g., amplification and/or attenuation) to each portion of thefeature-based voice data (e.g., each Mel channel), thus altering thespectral balance of the audio features (e.g., added noise) and addingdiversity to the training data. In some implementations, the applicationof different gain factors for different portions of feature-based voicedata may be guided by the target SNR such that the overall target SNR isachieved. For example, data augmentation process 10 may determine arange of gain factors to apply to each portion of feature-based voicedata based upon, at least in part, the target SNR.

In some implementations, data augmentation process 10 may train 920 amachine learning model with a plurality of audio features associatedwith the target acoustic domain. For example and as discussed above,data augmentation process 10 may train a neural network (e.g., machinelearning model 72) to add and/or remove audio features (e.g., speechfeatures, noise features, etc.) to feature-based voice data 1000 byproviding training data with various audio features associated with atarget acoustic domain. As discussed above and in some implementations,data augmentation process 10 may provide training data associated with atarget acoustic domain to machine learning model 72 and machine learningmodel 72 may determine audio features associated with the targetacoustic domain and/or a distribution of audio features for the targetacoustic domain.

In some implementations, performing 902 the one or more audiofeature-based augmentations on at least a portion of the feature-basedvoice data may include performing 922 the one or more audiofeature-based augmentations to the at least a portion of thefeature-based voice data using the trained machine learning modelconfigured to model the plurality of audio features associated with thetarget acoustic domain. For example, a neural network (e.g., machinelearning model 72) may be trained to add one or more audio features toand/or remove one or more audio features from the feature-based voicedata with the input of a target acoustic domain and/or a selection togenerate more diverse training data. While an example of a neuralnetwork has been described, it will be appreciated that any artificialintelligence or machine learning system may be trained to perform theone or more audio feature-based augmentations within the scope of thepresent disclosure. Accordingly, data augmentation process 10 may traina neural network (e.g., machine learning model 72) to include particularaudio features and/or to include a particular distribution of audiofeatures associated with a target acoustic domain directly in thefeature domain.

Reverberation-Based Augmentations of Feature-Based Voice Data

Referring also to FIG. 11 and in some implementations, data augmentationprocess 10 may receive 1100 feature-based voice data associated with afirst acoustic domain. One or more reverberation-based augmentations maybe performed 1102 on at least a portion of the feature-based voice data,thus defining reverberation-augmented feature-based voice data.

As will be discussed in greater detail below, a reverberation-basedaugmentation may generally include any augmentation in the spectralmagnitude and/or phase of the feature-based voice data representative ofthe effect(s) of reverberation. For example, reverberation generallydescribes when a sound or signal is reflected causing numerousreflections to build up and then decay as the sound is absorbed bysurrounding surfaces. In some implementations, reverberation may bemeasured as T₆₀, the time it takes for the sound pressure level toreduce by 60 decibels (dB), and/or C₅₀, the measure of “early soundenergy” (e.g., energy received between 0 milliseconds and 50milliseconds) and “late sound energy” (e.g., energy received after 50milliseconds). It will be appreciated that other metrics for measuringthe effects of reverberation may be used within the scope of the presentdisclosure.

As will be discussed in greater detail below, performing one or morereverberation-based augmentations on the at least a portion of thefeature-based voice data may include adding reverberation, removingreverberation (i.e., de-reverberation), adding echo, and/or removingecho (e.g., echo cancellation). Accordingly, it will be appreciated thatreverberation-based augmentations may generally include any change inthe spectral magnitude and/or phase of the feature-based voice data.

In some implementations, data augmentation process 10 may receive 1100feature-based voice data associated with a first acoustic domain. Asdiscussed above and in some implementations, feature-based voice datamay be generated by converting a signal or at least a portion of asignal to the feature domain. Referring again to the example of FIG. 3and in some implementations, data augmentation process 10 may receive200 an audio signal (e.g., audio signal 300) and may convert 202 theaudio signal from the time domain to the feature domain to generatefeature-based voice data (e.g., feature-based voice data 332) associatedwith the audio signal (e.g., audio signal 300). While an example hasbeen provided of converting a signal from the time domain to the featuredomain, it will be appreciated that a signal may be converted to thefeature domain from any domain, within the scope of the presentdisclosure.

In some implementations, data augmentation process 10 may perform 1102one or more reverberation-based augmentations on at least a portion ofthe feature-based voice data. Referring also to the example of FIG. 12and in some implementations, data augmentation process 10 may receive1100 feature-based voice data (e.g., feature-based voice data 1200)associated with a first acoustic domain. In the example of FIG. 12,feature-based voice data 1200 may include a plurality of featurecoefficients (e.g., Mel Filter bank coefficients, Mel-frequency cepstralcoefficients, etc.) represented as a spectrogram of a signal as afunction of frequency (on the vertical axis) and time (on the horizontalaxis) where the shade of each quadrant represents the amplitude of eachfeature coefficient. While one example of feature-based voice data hasbeen described, it will be appreciated that the feature-based voice datamay be represented in various ways within the scope of the presentdisclosure.

In some implementation, data augmentation process 10 may perform 1102one or more reverberation-based augmentations on at least a portion ofthe feature-based voice data associated with the first acoustic domain.As will be discussed in greater detail below, it may be desirable toaugment at least a portion of feature-based voice data associated with aparticular acoustic domain for various reasons.

For example and in some implementations, data augmentation process 10may perform 1102 one or more reverberation-based augmentations on atleast a portion of the feature-based voice data to utilize thefeature-based voice data for training a speech processing system in atarget acoustic domain. In this example, data augmentation process 10may train a speech processing system with feature-based voice data froma different acoustic domain which may allow for speech processingsystems to be effectively utilized in various acoustic domains using anaugmented set of training feature-based voice data.

In another example, data augmentation process 10 may perform 1102 one ormore reverberation-based augmentations on at least a portion of thefeature-based voice data to generate additional training data for speechprocessing systems with various audio features. In this manner, dataaugmentation process 10 may train speech processing systems to be morerobust against variations in reverberation by augmenting a set oftraining feature-based voice data with various reverberationcharacteristics. While two examples have been provided for utilizingreverberation-based augmented feature-based voice data, it will beappreciated that data augmentation process 10 may perform 1102reverberation-based augmentations on feature-based voice data for otherpurposes within the scope of the present disclosure. For example and insome implementations, reverberation-based augmentations may be used toadapt a speech processing system with new adaptation data (e.g.,reverberation-based augmentations).

As discussed above, after a signal is converted to the feature domain,it may be impossible to determine certain acoustic properties of thesignal without converting the signal back to the time domain. In someimplementations, when receiving 1100 the feature-based voice data, dataaugmentation process 10 may also receive information associated with thefeature-based voice data. In some implementations, the informationassociated with the feature-based voice data may include only generalinformation about the feature-based voice data. For example, theinformation may identify the feature-based voice data as being recordedin a general acoustic domain (e.g., a particular reverberationmeasurement (e.g., expressed as a C₅₀ value)). In some implementations,the information may or may not be specific to the feature-based voicedata. For example, the information may provide general characteristicsassociated with the feature-based voice data.

In some implementations, processing 204 the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata may include performing 216 one or more reverberation-basedaugmentations on at least a portion of the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata. As discussed above, data augmentation process 10 may extract200 acoustic metadata from the signal before the signal is converted 202to the feature domain. As discussed above, the extracted acousticmetadata may include global acoustic metadata associated with a signalgenerally and/or acoustic metadata associated with or specific toparticular portions of the signal. In this manner, the extractedacoustic metadata may provide more specific information about theacoustic domain of the feature-based voice data than available fromother more generalized information about the feature-based voice data.As will be discussed in greater detail below and in someimplementations, the acoustic metadata associated (e.g., acousticmetadata 1202) with a signal may allow data augmentation process 10 todetermine various characteristics of the feature-based voice data andperform 216 one or more reverberation-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic domain of the feature-based voicedata.

In some implementations, data augmentation process 10 may receive 1104 aselection of a target acoustic domain. As discussed above, a targetacoustic domain may generally include a target set of factors andcharacteristics that define the quality of a signal. In someimplementations, data augmentation process 10 may receive 1104 aselection of a target acoustic domain by providing particularreverberation-based characteristics associated with the target acousticdomain (e.g., reverberation measured in T₆₀, C₅₀, etc.). In someimplementations, data augmentation process 10 may utilize a graphicaluser interface for receiving 1104 a selection of a target acousticdomain from a library of predefined acoustic domains. In one example,data augmentations process 10 may receive selections (e.g., via agraphical user interface) of various characteristics of the acousticdomain (e.g., a selection of the reverberation, signal-to-noise ratio(SNR), a type of microphone array, a particular noise track, etc.) todefine a target acoustic domain. As will be discussed in greater detailbelow and in some implementations, data augmentation process 10 mayreceive a range or distribution of characteristics for the targetacoustic domain.

In one example, suppose a speech processing system is trained forprocessing speech in a particular acoustic domain (e.g., a telephoneconference where a speaker is talking very close to the microphone). Inthis example, because the speaker is speaking very close to themicrophone, there will be minimal reverberation.

However, other acoustic domains may receive and process speech withdifferent reverberation characteristics. For example, suppose amicrophone is deployed in a conference room where the microphones arepositioned on a table a few meters away from the speakers. In thisexample, the reverberation of the feature-based voice data may be morepronounced than the reverberation from that of a speaker speaking veryclose to the microphone. In this example, data augmentation process 10may receive 1104 a selection of a target acoustic domain (e.g., a targetacoustic domain associated with a conference room where the microphonesare positioned on a table a few meters away from the speakers). While anexample of a particular target acoustic domain has been provided, itwill be appreciated that various target acoustic domains may be selectedwithin the scope of the present disclosure.

In some implementations, performing 1102 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data may include performing 1106 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data based upon, at least in part, the targetacoustic domain. Returning to the above example, suppose dataaugmentation process 10 receives 1104 a selection of the acoustic domainassociated with a conference room where the microphones are positionedon a table a few meters away from the speakers. In this example, dataaugmentation process 10 may perform 1106 one or more reverberation-basedaugmentations on at least a portion of the feature-based voice data ofthe first acoustic domain (e.g., the acoustic domain associated with atelephone conference where a speaker is talking very close to themicrophone).

In some implementations, data augmentation process 10 may perform 1106one or more reverberation-based augmentations on at least a portion offeature-based voice data 1200 to account for the variations inreverberation. Accordingly, data augmentation process 10 may perform1106 reverberation-based augmentations to map feature-based voice data1200 from the first acoustic domain (e.g., the acoustic domainassociated with a telephone conference where a speaker is talking veryclose to the microphone) to a target acoustic domain (e.g., the acousticdomain associated with a conference room where the microphones arepositioned on a table a few meters away from the speakers). In thismanner, a speech processing system may be trained using feature-basedvoice data from one acoustic domain for processing speech in anotheracoustic domain.

In some implementations, data augmentation process 10 may determine adistribution of reverberation levels associated with the target acousticdomain. For example and in some implementations, when performing 1106the one or more reverberation-based augmentations on feature-based voicedata associated with a first acoustic domain for use in a targetacoustic domain, the target acoustic domain may not have a constantreverberation level present in recordings captured within the targetacoustic domain. In this example, data augmentation process 10 maydetermine a distribution of reverberations associated with the targetacoustic domain. For example, data augmentation process 10 may processtraining data (e.g., time domain data and/or feature-based voice data)from the target acoustic domain to determine a distribution ofreverberation levels. In some implementations, determining thedistribution of reverberation from training data associated with thetarget acoustic domain may include determining how the reverberationwithin the training data varies over time for particular frequencies orfrequency bands. In this manner, data augmentation process 10 maydetermine a distribution of reverberation levels to add or remove whenperforming reverberation-based augmentations on the feature-based voicedata associated with the first acoustic domain.

In some implementations, performing 1112 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data may include performing the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data based upon, at least in part, the distributionof reverberation levels associated with the target acoustic domain. Asdiscussed above, with a distribution of reverberation levels associatedwith the target domain, data augmentation process 10 may perform one ormore reverberation-based augmentations on at least a portion of thefeature-based voice data to include a similar distribution ofreverberation levels as the target acoustic domain.

In some implementations, suppose data augmentation process 10 determinesa distribution of reverberation levels (e.g., distribution ofreverberation levels 1204) associated with the target acoustic domain(e.g., the acoustic domain associated with a conference room where themicrophones are positioned on a table a few meters away from thespeakers). In this example, data augmentation process 10 may perform oneor more reverberation-based augmentations on the feature-based voicedata (e.g., feature-based voice data 1200) associated with the firstacoustic domain (e.g., the acoustic domain associated with a telephoneconference where a speaker is talking very close to the microphone) toinclude a similar or the same distribution of reverberation levels as inthe target acoustic domain.

As will be discussed in greater detail below, data augmentation process10 may perform these reverberation-based augmentations on feature-basedvoice data 1200 by adding reverberation to and/or removing reverberationfrom feature-based voice data 1200 based upon, at least in part, thedistribution of reverberation levels associated with the target domain.In this manner, data augmentation process 10 may allow feature-basedvoice data 1200 associated with one acoustic domain (e.g., the acousticdomain associated with a telephone conference where a speaker is talkingvery close to the microphone) to be used to train speech processingsystems in a target acoustic domain (e.g., the acoustic domainassociated with a conference room where the microphones are positionedon a table a few meters away from the speakers), thus definingreverberation-augmented feature-based voice data (e.g.,reverberation-augmented feature-based voice data 1206).

While an example of performing one or more reverberation-basedaugmentations on at least a portion of feature-based voice data has beendescribed for augmenting feature-based voice data to include a similardistribution of reverberation levels as that of a target acousticdomain, it will be appreciated that data augmentation process 10 mayperform one or more reverberation-based augmentations on at least aportion of feature-based voice data for other purposes within the scopeof the present disclosure. As discussed above, data augmentation mayallow an existing set of training data to be used in other acousticdomains or to provide more diverse training data within the sameacoustic domain.

For example, suppose that a speech processing system is trained withtraining data having particular a reverberation level (e.g., measured inT₆₀, C₅₀, etc.). If a speech processing system is exposed to speechsignals with reverberation levels that vary from the training data, thespeech processing system may be less effective in processing the speechsignal. In this manner, data augmentation process 10 may perform 1102one or more reverberation-based augmentations on at least a portion ofthe feature-based voice data to generate more diverse training data fora speech processing system (e.g., training data with varyingreverberation).

In some implementations, performing 1102 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data may include adding 1108 reverberation to the atleast a portion of the feature-based voice data. For example, supposethat data augmentation process 10 receives 1100 feature-based voice data1200 associated with a first acoustic domain (e.g., an acoustic domainassociated with a telephone conference where a speaker is talking veryclose to the microphone) and receives 1104 a selection of a targetacoustic domain (e.g., an acoustic domain associated with a conferenceroom where the microphones are positioned on a table a few meters awayfrom the speakers).

Data augmentation process 10 may determine that the target acousticdomain has a particular reverberation level or distribution ofreverberation levels (e.g., measured in T₆₀, C₅₀, etc.) and thatfeature-based voice data 1200 has a different reverberation level ordistribution. In this example, as feature-based voice data is recordedby a microphone positioned close to the speaker and the target acousticdomain is conference room where the microphones are positioned on atable a few meters away from the speakers, the reverberation level ofthe target acoustic domain is likely to be higher than the reverberationlevel recorded in feature-based voice data 1200. Accordingly, dataaugmentation process 10 may perform 1102 one or more reverberation-basedaugmentations by adding 1108 reverberation to at least a portion offeature-based voice data 1200 based upon, at least in part, the targetacoustic domain.

In some implementations, performing 1102 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data may include removing 1110 reverberation to theat least a portion of the feature-based voice data. For example, supposethat data augmentation process 10 receives 1100 feature-based voice data1200 associated with a first acoustic domain (e.g., an acoustic domainassociated with a conference room where the microphones are positionedon a table a few meters away from the speakers) and receives 1104 aselection of a target acoustic domain (e.g., an acoustic domainassociated with a telephone conference where a speaker is talking veryclose to the microphone).

Data augmentation process 10 may determine that the target acousticdomain has a particular reverberation level or distribution ofreverberation levels (e.g., measured in T₆₀, C₅₀, etc.) and thatfeature-based voice data 1200 has a different reverberation level ordistribution. In this example, as feature-based voice data is recordedin a conference room where the microphones are positioned on a table afew meters away from the speakers and the target acoustic domain is atelephone conference where a speaker is talking very close to themicrophone, the reverberation level of the target acoustic domain islikely to be lower than the reverberation level recorded infeature-based voice data 1200. Accordingly, data augmentation process 10may perform 1102 one or more reverberation-based augmentations byremoving 1110 reverberation to at least a portion of feature-based voicedata 1200 based upon, at least in part, the target acoustic domain.

In some implementations, data augmentation process 10 may perform 1102the one or more reverberation-based augmentations by applying a gainfactor to augment the effect of reverberation. For example, dataaugmentation process 10 may apply a channel-dependent gain factor to oneor more channels of feature-based voice data 1200 (e.g., one or more Melchannels). In one example, data augmentation process 10 may apply achannel-dependent gain factor to each channel of feature-based voicedata 1200. In this manner, data augmentation process 10 may add 1108and/or remove 1110 reverberation to at least a portion of feature-basedvoice data 1200 by applying one or more channel-dependent gain factors.

In some implementations, data augmentation process 10 may perform 1102the one or more reverberation-based augmentations by applying a decayingfunction (e.g., a decaying exponential function) to augment the effectof reverberation. For example, data augmentation process 10 may apply adecaying function to one or more channels of feature-based voice data1200. In one example, data augmentation process 10 may apply differentdecaying functions to each channel of feature-based voice data 1200.Accordingly, the decaying function(s) may directly influence thereverberation level in each channel of feature-based voice data 1200(e.g., as reverberation-augmented feature-based voice data 1206).

As discussed above, reverberation may be a function of the environmentof the signal (e.g., how the signal reflects off of objects in the roomadjacent to the signal source). Accordingly, in order to model theeffects of reverberation, a room impulse response may be generated.However, applying a room impulse response in the feature domain usingconventional data augmentation techniques is not feasible. For example,conventional data augmentation techniques require a signal to beconverted back to the time domain. A room impulse response is typically300 to 600 milliseconds long. As such, to model reverberation, a largeframe size in the frequency domain is required. However, frames forspeech processing systems are typically between 20 to 35 millisecondslong. Accordingly, a simple multiplication of feature-based voice data1200 with a feature domain representation of a room impulse response maynot augment feature-based voice data 1200 to include reverberation basedupon, at least in part, the room impulse response.

In some implementations, data augmentation process 10 may train 1112 amachine learning model with one or more room impulse responsesassociated with the target acoustic domain. Referring also to theexample of FIG. 13 and in some implementations, data augmentationprocess 10 may train a machine learning model (e.g., a neural network)to mimic the effect of reverberation by “learning” a filter in thefeature domain. In one example, the machine learning model (e.g.,machine learning model 72) may include a convolutional neural network(CNN) trained with training data (e.g., clean speech) and one or moreroom impulse responses associated with a target acoustic domain. Whilean example of a convolutional neural network has been described formachine learning model 72, it will be appreciated that any neuralnetwork, deep learning system, artificial intelligence system, or othermachine learning model may be used within the scope of the presentdisclosure.

In some implementations, the room impulse response may be measured in anactual room and/or may be simulated using various algorithms known inthe art. In some implementations, machine learning model 72 may trainwith e.g., one filter and linear activations based upon feature-basedvoice data (e.g., number of channels in the feature domain, nMel) and anumber of frames based upon the reverberation level (e.g., the measuredT₆₀). In one example, the number of frames may be 12. However, it willbe appreciated that any number of frames may be utilized within thescope of the present disclosure. In some implementations, the trainedmachine learning model may output a trained filter template (e.g.,filter 1300) configured to augment feature-based voice data with aparticular reverberation level or distribution of reverberation levelsin the feature domain.

In some implementations, performing 1102 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data may include performing 1114 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data using the trained machine learning modelconfigured to model the reverberation associated with the targetacoustic domain. For example, once the filter template(s) are trained,data augmentation process 10 may perform 1114 the one or morereverberation-based augmentations to the at least a portion of thefeature-based voice data using the trained machine learning model (e.g.,machine learning model 72) by applying the trained filter template(e.g., filter 1300) to feature-based voice data 1200. In one example,machine learning model 72 may apply filter 1300 in a manner similar toconvolution in image processing (e.g., where the “image” in this exampleis a section of feature-based voice data 1200 (e.g., the Mel spectrum)and filter 1300 captures the time/frequency dependent smearing effect ofa room impulse response). Accordingly, data augmentation process 10 maytrain filter 1300 once on a small dataset and then can be applied to anyfeature-based voice data directly in the feature domain (e.g., the Meldomain).

Machine Learning Model Feature-Based Voice Data Augmentation

In some implementations, data augmentation process 10 may receive 1400feature-based voice data. One or more data augmentation characteristicsmay be received 1402. One or more augmentations of the feature-basedvoice data may be generated 1404, via a machine learning model, basedupon, at least in part, the feature-based voice data and the one or moredata augmentation characteristics.

As will be discussed in greater detail below, data augmentation process10 may allow a machine learning model to generate 1404 one or moreaugmentations of feature-based voice data in the feature domain withoutaccessing the original signal (e.g., in the time domain) by training themachine learning model with several examples of original signals (e.g.,in the time domain) and augmented feature-based voice data (e.g., in thefeature domain). In this manner, data augmentation process 10 maygenerate 1404 augmented feature-based voice data with inputfeature-based voice data and particular data augmentationcharacteristics without accessing the time domain version of the inputfeature-based voice data.

As will be discussed in greater detail below, process 10 may allow amachine learning model to generate 1404 augmented training data withoutrequiring the machine learning model to be trained with equivalent timedomain data from various acoustic domains. For example, conventionaldata augmentation techniques may allow a mapping of one image domain toanother image domain by training systems with the same recorded datafrom each image domain. However, the ability to capture training data ineach set of domains may be impractical for these techniques and may notallow speech processing systems to be fully trained for an acousticdomain until time domain signals are recorded in each domain. In someimplementations, data augmentation process 10 may train a machinelearning model to perform complex combinations of augmentations, asopposed augmentations from a single domain to another domain. Forexample, by training the machine learning model with training datarequiring various augmentations, data augmentation process 10 maygenerate 1404 augmented feature-based voice data directly in the featuredomain by utilizing the training of individual augmentation parameters.In this manner, the trained machine learning model may be able togeneralize augmentations outside of the bounds of specific trainingdata.

In some implementations, data augmentation process 10 may train amachine learning model to perform one or more augmentations on at leasta portion of feature-based voice data. Referring also to the example ofFIG. 15 and in some implementations, a machine learning model (e.g.,machine learning model 1500) may be configured to receive one or moresignals in the time domain (e.g., signal 1502), one or moreaugmentations of the one or more signals in the time domain (e.g.,augmented time domain signal 1504), feature-based voice data associatedwith the one or more signals (e.g., feature-based voice data 1506), andaugmentations of the feature-based voice data corresponding to the oneor more augmentations of the one or more signals in the time domain(e.g., augmented feature-based voice data 1508). In someimplementations, data augmentation process 10 may perform one or moreaugmentations (e.g., defined by conditioning vector 1510) on signal 1502to generate augmented time domain signal 1504 and may convert augmentedtime domain signal 1504 to the feature domain to generate augmentedfeature-based voice data 1508. As will be discussed in greater detailbelow, data augmentation process 10 may utilize augmented feature-basedvoice data 1508 to train machine learning model 1500.

In some implementations and as will be discussed in greater detailbelow, training machine learning model 1500 may include tuning variousaugmentation parameters associated with augmenting feature-based voicedata. Referring again to the example of FIG. 15 and in someimplementations, data augmentation process 10 may receive feature-basedvoice data 1506 converted from signal 1502. However, in someembodiments, data augmentation process 10 may receive signal 1502 andconvert signal 1502 to the feature domain to generate feature-basedvoice data 1506.

In some implementations, data augmentation process 10 may receiveconditioning vector 1510 describing the augmentations to perform onsignal 1502 and/or feature-based voice data 1506. For example,conditioning vector 1510 may define various desired characteristics forthe augmented signal or augmented feature-based voice data. Examples ofthe augmentation characteristics defined by conditioning vector 1510 maygenerally include a noise type, a target SNR, a T₆₀ value, a C₅₀ value,etc. As will be described in greater detail below, conditioning vector1510 may be an example of one or more data augmentation characteristicsreceived by data augmentation process 10 and used to generate one ormore augmentations of feature-based voice data.

In some implementations, data augmentation process 10 may processfeature-based voice data 1506 and conditioning vector 1510 to performone or more augmentations on feature-based voice data 1506. In someimplementations, machine learning model 1500 may be configured withvarious parameters associated with different types of augmentations thatmay be performed on at least a portion of feature-based voice data 1506.For example, machine learning model 1500 may be configured to performvarious types of augmentations represented by different tunableaugmentation parameters or combination of tunable parameters (e.g.,tunable augmentation parameters 1512, 1514, 1516, 1518, 1520). Examplesof these types of augmentations may include one or more gain-basedaugmentations (e.g., represented by tunable augmentation parameter1512); one or more rate-based augmentations (e.g., represented bytunable augmentation parameter 1514); one or more audio feature-basedaugmentations (e.g., represented by tunable augmentation parameter1516); and one or more reverberation-based augmentations (e.g.,represented by tunable augmentation parameter 1518). However, it will beappreciated that any type of augmentation or number of augmentations maybe performed by machine learning model 1500 within the scope of thepresent disclosure.

As shown in the example of FIG. 15 and in some implementations, dataaugmentation process 10 may (e.g., via machine learning model 1500)process conditioning vector 1510 to determine which augmentations toperform on feature-based voice data 1506. For example, suppose thatconditioning vector 1510 describes a particular gain for a particularfrequency band; a particular speaking rate; a type of noise; and areverberation level (e.g., defined as a T₆₀ value). In this example,data augmentation process 10 may (e.g., via machine learning model 1500)perform one or more gain-based augmentations based upon the particulargain for the specified frequency band to generate gain-augmentedfeature-based voice data 1522; one or more rate-based augmentationsbased upon the specified speaking rate to generate rate-based augmentedfeature-based voice data 1524; one or more audio feature-basedaugmentations to add the specified type of noise to generate audiofeature-augmented feature-based voice data 1526; one or morereverberation-based augmentations to achieve the desired T₆₀ value togenerate reverberation-augmented feature-based voice data 1528; andother augmented feature-based voice data 1530.

In some implementations, data augmentation process 10 may train machinelearning model 1500 based upon, at least in part, the time domainaugmentations and the augmented feature-based voice data correspondingto the one or more time domain augmentations by minimizing an errorbetween the augmented feature-based voice data and the correspondingtime domain augmentations. Referring again to the example of FIG. 15 andin some implementations, data augmentation process 10 may (e.g., viamachine learning model 1500) compare the augmented feature-datagenerated by machine learning model (e.g., augmented feature-based voicedata 1522, 1524, 1526, 1528, 1530) based upon, at least in part,conditional vector 510 with the augmentations of the feature-based voicedata corresponding to the one or more augmentations of the one or moresignals in the time domain (e.g., augmented feature-based voice data1508).

In some implementations, data augmentation process 10 may minimize anerror (e.g., via error minimization process 1532) associated with acomparison of the augmented feature-data generated by machine learningmodel 1500 (e.g., augmented feature-based voice data 1522, 1524, 1526,1528, 1530) and the one or more augmentations of the one or more signalsin the time domain (e.g., augmented feature-based voice data 1508). Insome implementations, minimizing the error (e.g., via error minimizationprocess 1532) may include adjusting the tunable augmentation parameters(e.g., tunable augmentation parameters 1512, 1514, 1516, 1518, 1520). Inthis manner, machine learning model 1500 may be configured to “learn”how to augment feature-based voice data across various tunableaugmentation parameters.

In some implementations, data augmentation process 10 may receive 1400feature-based voice data. Accordingly, data augmentation process 10 mayextract 1406 acoustic metadata from the audio signal before converting1408 the audio signal from the time domain to the feature domain. Asdiscussed above, acoustic metadata may generally refer to informationregarding the characteristics or properties of the signal. In someimplementations, the acoustic metadata may only refer to properties ofthe signal without exposing or describing any speech content of thesignal.

In some implementations, data augmentation process 10 may receive 1402one or more data augmentation characteristics. Referring also to theexample of FIG. 16 and in some implementations, data augmentationprocess 10 may receive 1402 one or more data augmentationcharacteristics (e.g., data augmentation characteristics 1600). In someimplementations, data augmentation characteristics 1600 may be receivedvia a user interface from one or more menus for selecting particulardata augmentations to perform on feature-based voice data (e.g.,feature-based voice data 1602). However, it will be appreciated thatdata augmentation characteristics 1600 may be received in various wayswithin the scope of the present disclosure.

As discussed above and in some implementations, data augmentationcharacteristics 1600 may define various desired characteristics for theaugmented feature-based voice data (e.g., augmented feature-based voicedata 1604). Examples of data augmentation characteristics that may bedefined may generally include a noise type, a target SNR, a T₆₀ value, aC₅₀ value, etc. In some implementations, data augmentation process 10may receive one or more data augmentation characteristics (e.g., dataaugmentation characteristics 1600) as one or more conditioning vectors(e.g., a vector-based representation of desired characteristics for theaugmented feature-based voice data). However, it will be appreciatedthat the one or more data augmentation characteristics may be receivedin various formats within the scope of the present disclosure.

In some implementations, data augmentation process 10 may generate 1404,via a machine learning model, one or more augmentations of thefeature-based voice data based upon, at least in part, the feature-basedvoice data and the one or more data augmentation characteristics.Referring again to the example of FIG. 16 and in some implementations,suppose data augmentation process 10 receives 1400 feature-based voicedata 1602. As discussed above, feature-based voice data 1602 may includea feature domain representation of signal with various featurecoefficients. For example, feature-based voice data 1602 may include aplurality of dimensions or feature coefficients (e.g., Mel frequencycepstral coefficients, Mel Filter Bank coefficients, etc.). Furthersuppose that data augmentation process 10 receives 1402 one or more dataaugmentation characteristics (e.g., data augmentation characteristics1600) describing one or more desired characteristics for the augmentedfeature-based voice data (e.g., augmented feature-based voice data1604).

In some implementations, generating 1404, via the machine learningmodel, the one or more augmentations of the feature-based voice data mayinclude generating 1410, via the machine learning model, the one or morefeature-based augmentations of the feature-based voice data based upon,at least in part, the feature-based voice data, the one or more dataaugmentation characteristics, and the acoustic metadata. Referring againto the example of FIG. 16 and as discussed above, data augmentationprocess 10 may extract 1406 acoustic metadata (e.g., acoustic metadata1606) associated with feature-based voice data 1602 before convertingthe signal to the feature domain. In some implementations, acousticmetadata 1606 may describe the acoustic characteristics of feature-basedvoice data 1602 and/or portion of feature-based voice data 1602.Examples of acoustic characteristics may generally include a gain level,presence of a speech component, presence and type of a noise component,a speaking rate, a reverberation level, etc. In some implementations,acoustic metadata 1606 may provide machine learning model 1500 with asignal-specific “starting point” for augmenting feature-based voice data1602.

For example and as discussed above, when a signal is converted to thefeature domain, it may be impossible to determine acousticcharacteristics of the signal without converting the signal back to thetime domain and potentially exposing speech content. To avoid thischallenge, acoustic metadata 1606 may describe these acousticcharacteristics of a signal such that any augmentations of featuredomain representation of the signal may be specific to feature-basedvoice data 1602. In some implementations without extracting acousticmetadata 1606, machine learning model 1500 may receive some generalinformation associated with the acoustic characteristics offeature-based voice data (e.g., a categorization of feature-based voicedata as speech recorded in a vehicle). With only this generalinformation, the augmentations performed may be less tailored andaccurate when applied to feature-based voice data 1602 than whenaugmentations are performed based upon, at least in part, acousticmetadata 1606. Accordingly, data augmentation process 10 may utilizeacoustic metadata 1606 to determine which augmentations to perform onfeature-based voice data 1602 to generate augmented feature-based voicedata 1604 based upon, at least in part, data augmentationcharacteristics 1600.

In some implementations, generating 1404, via the machine learningmodel, the one or more augmentations of the feature-based voice data mayinclude performing 1412, via the machine learning model, one or moregain-based augmentations on at least a portion of the feature-basedvoice data based upon, at least in part, the feature-based voice dataand the one or more data augmentation characteristics. Referring againto the example of FIG. 16, suppose that feature-based voice data 1602 isassociated with a first acoustic domain (e.g., an acoustic domainassociated with a speaker speaking directly into a microphone within alaboratory). In some implementations, specific gain level informationmay be determined from acoustic metadata 1606 extracted from the timedomain signal of feature-based voice data 1602.

Continuing with the above example, suppose that data augmentationcharacteristics 1600 describe a distribution of gain levels for variousfrequencies. In this example, data augmentation process 10 may (e.g.,via machine learning model 1500) utilize the trained parametersassociated with gain-based augmentations (e.g., represented as parameter1512) to generate 1404 augmented feature-based voice data 1608. In thisexample and as discussed above, machine learning model 1500 may perform1412 one or more gain-based augmentations on at least a portion offeature-based voice data 1602 such that gain-augmented feature-basedvoice data 1608 includes the distribution of gain levels for thefrequencies specified by data augmentation characteristics 1600. Whilethe example of FIG. 16 shows gain-augmented feature-based voice dataseparately from other augmented feature-based voice data, it will beappreciated that machine learning model 1500 may perform 1412 the one ormore gain-based augmentations to feature-based voice data 1602 inparallel and/or simultaneously with other augmentations within the scopeof the present disclosure.

In some implementations, generating 1404, via the machine learningmodel, the one or more augmentations of the feature-based voice data mayinclude performing 1414, via the machine learning model, one or morerate-based augmentations on at least a portion of the feature-basedvoice data based upon, at least in part, the feature-based voice dataand the one or more data augmentation characteristics. Referring againto the example of FIG. 16 and as discussed above, suppose thatfeature-based voice data 1602 is associated with a first acoustic domain(e.g., an acoustic domain where a speaker speaks into a microphonedictation system configured to recognize and transcribe speech). In someimplementations, a particular speaking rate or distribution of speakingrates may be determined from acoustic metadata 1606 extracted from thetime domain signal of feature-based voice data 1602.

Continuing with the above example, suppose that data augmentationcharacteristics 1600 describe a distribution of speaking rates. In thisexample, data augmentation process 10 may (e.g., via machine learningmodel 1500) utilize the trained parameters associated with rate-basedaugmentations (e.g., represented as parameter 1514) to generate 1404augmented feature-based voice data 1610. In this example and asdiscussed above, machine learning model 1500 may perform 1414 one ormore rate-based augmentations on at least a portion of feature-basedvoice data 1602 such that rate-based augmented feature-based voice data1610 includes the distribution of speaking rates specified by dataaugmentation characteristics 1600.

In some implementations, generating 1404, via the machine learningmodel, the one or more augmentations of the feature-based voice data mayinclude performing 1416, via the machine learning model, one or moreaudio feature-based augmentations on at least a portion of thefeature-based voice data based upon, at least in part, the feature-basedvoice data and the one or more data augmentation characteristics.Referring again to the example of FIG. 16 and as discussed above,suppose that feature-based voice data 1602 is associated with a firstacoustic domain (e.g., an acoustic domain associated with a medicalprofessional's office including a microphone array configured to processconversations between medical professionals and patients). In someimplementations, specific audio feature(s) may be determined fromacoustic metadata 1606 extracted from the time domain signal offeature-based voice data 1602.

Continuing with the above example, suppose that data augmentationcharacteristics 1600 describe a distribution of noise features acrossvarious frequencies (e.g., noise features associated with noise capturedwhile capturing speech within a particular type of vehicle). In thisexample, data augmentation process 10 may (e.g., via machine learningmodel 1500) utilize the trained parameters associated with audiofeature-based augmentations (e.g., represented as parameter 1516) togenerate 1404 augmented feature-based voice data 1612. In this exampleand as discussed above, machine learning model 1500 may perform 1416 oneor more audio feature-based augmentations on at least a portion offeature-based voice data 1602 such that audio feature-augmentedfeature-based voice data 1612 includes the distribution of noisefeatures for the frequencies specified by data augmentationcharacteristics 1600.

In some implementations, generating 1404, via the machine learningmodel, the one or more augmentations of the feature-based voice data mayinclude performing 1418, via the machine learning model, one or morereverberation-based augmentations on at least a portion of thefeature-based voice data based upon, at least in part, the feature-basedvoice data and the one or more data augmentation characteristics.Referring again to the example of FIG. 16 and as discussed above,suppose that feature-based voice data 1602 is associated with a firstacoustic domain (e.g., an acoustic domain associated with a speakerspeaking into a microphone array deployed in an enclosed office space).In some implementations, a specific reverberation level (e.g., definedas a T₆₀ value) may be determined from acoustic metadata 1606 extractedfrom the time domain signal of feature-based voice data 1602.

Suppose that data augmentation characteristics 1600 describe adistribution of reverberation (e.g., T₆₀ values associated with aconference room and microphones placed on a table a few meters away fromthe speakers). In this example, data augmentation process 10 may (e.g.,via machine learning model 1500) utilize the trained parametersassociated with reverberation-based augmentations (e.g., represented asparameter 1518) to generate 1404 augmented feature-based voice data1614. In this example and as discussed above, machine learning model1500 may perform 1418 one or more reverberation-based augmentations onat least a portion of feature-based voice data 1602 such thatreverberation-augmented feature-based voice data 1614 includes thereverberation specified by data augmentation characteristics 1600.

While the above examples describe generating 1404 the one or moreaugmentations separately, it will be appreciated that the one or moreaugmentations may be performed in parallel and/or simultaneously withinthe scope of the present disclosure. It will also be appreciated thatthe above example types of augmentations are for example purposes onlyand do not preclude other types of augmentations that may be performedwithin the scope of the present disclosure.

In some implementations, data augmentation process 10 may train a speechprocessing system using the augmented feature-based voice data. Asdiscussed above and in some implementations, data augmentation process10 may generate augmented feature-based voice data that, when used inthe training of a speech processing system, allows the speech processingsystem to be more robust against such acoustic variations. In someimplementations, training a speech processing system may generallyinclude training one or more speech processing models (e.g., machinelearning or neural network models) configured to process a speech signalfor various purposes. For example, speech processing system maygenerally include an automated speech recognition (ASR) system, a voicebiometric system, emotion detection system, medical symptom detectionsymptom, hearing enhancement system, etc. In one example, training aspeech processing system may include training an ASR system configuredto process a speech signal to generate recognized speech. In thismanner, an automated speech recognition system may be improved torecognize speech signals with acoustic variations resulting from amoving speaker and/or adaptive beamforming. While an example of ASRsystem has been provided, it will be appreciated that any speechprocessing system may be trained within the scope of the presentdisclosure.

In some implementations, automated speech recognition may be performedvia the trained speech processing system executed on the same computingdevice that trained the speech processing system and/or on anothercomputing device. Accordingly, it will be appreciated that generatingaugmented data (e.g., augmented feature-based voice data), training aspeech processing system with the augmented data, and performing speechprocessing via the trained speech processing system may be performed onthe same computing device and/or discrete computing devices within thescope of the present disclosure.

In some implementations, data augmentation process 10 may perform speechprocessing via the trained speech processing system, where the trainedspeech processing system is executed on at least one computing device.For example, embodiments of data augmentation process 10 may be used inambient speech applications, such as Dragon® Speech Recognition Softwareavailable from Nuance Communications, Inc. of Burlington, Mass., withmultiple, distant microphones or for a health care application where thedoctor and patient speech is acquired through a microphone array (e.g.,using Dragon® Ambient eXperience™ (DAX)); Dragon is a registeredtrademark of Nuance Communications, Inc. in the United States, othercountries or both. In some implementations, embodiments of dataaugmentation process 10 may be utilized to enhance ASR performance invarious settings (e.g., voice-based vehicular control systems,voice-based dialogue systems, etc.). In some implementations, speechprocessing may be performed via the trained speech processing systemexecuted on the same computing device that trained the speech processingsystem and/or on another computing device. Accordingly, it will beappreciated that generating augmented data (e.g., augmentedfeature-based voice data), training a speech processing system with theaugmented data, and performing speech processing via the trained speechprocessing system may be performed on the same computing device and/ordiscrete computing devices within the scope of the present disclosure.

Referring also to FIG. 17, there is shown a diagrammatic view of clientelectronic device 38. While client electronic device 38 is shown in thisfigure, this is for illustrative purposes only and is not intended to bea limitation of this disclosure, as other configurations are possible.For example, any computing device capable of executing, in whole or inpart, data augmentation process 10 may be substituted for clientelectronic device 38 within FIG. 17, examples of which may include butare not limited to computing device 12 and/or client electronic devices40, 42, 44.

Client electronic device 38 may include a processor and/ormicroprocessor (e.g., microprocessor 1700) configured to, e.g., processdata and execute the above-noted code/instruction sets and subroutines.Microprocessor 1700 may be coupled via a storage adaptor (not shown) tothe above-noted storage device(s) (e.g., storage device 30). An I/Ocontroller (e.g., I/O controller 1702) may be configured to couplemicroprocessor 1700 with various devices, such as keyboard 1704,pointing/selecting device (e.g., mouse 1706), custom device, such amicrophone (e.g., device 1708), USB ports (not shown), and printer ports(not shown). A display adaptor (e.g., display adaptor 1710) may beconfigured to couple display 1712 (e.g., CRT or LCD monitor(s)) withmicroprocessor 1700, while network controller/adaptor 1714 (e.g., anEthernet adaptor) may be configured to couple microprocessor 1700 to theabove-noted network 14 (e.g., the Internet or a local area network).

As will be appreciated by one skilled in the art, the present disclosuremay be embodied as a method, a system, or a computer program product.Accordingly, the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,the present disclosure may take the form of a computer program producton a computer-usable storage medium having computer-usable program codeembodied in the medium.

Any suitable computer usable or computer readable medium may beutilized. The computer-usable or computer-readable medium may be, forexample but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. More specific examples (a non-exhaustive list) ofthe computer-readable medium may include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a transmission media such as those supportingthe Internet or an intranet, or a magnetic storage device. Thecomputer-usable or computer-readable medium may also be paper or anothersuitable medium upon which the program is printed, as the program can beelectronically captured, via, for instance, optical scanning of thepaper or other medium, then compiled, interpreted, or otherwiseprocessed in a suitable manner, if necessary, and then stored in acomputer memory. In the context of this document, a computer-usable orcomputer-readable medium may be any medium that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-usable medium may include a propagated data signal with thecomputer-usable program code embodied therewith, either in baseband oras part of a carrier wave. The computer usable program code may betransmitted using any appropriate medium, including but not limited tothe Internet, wireline, optical fiber cable, RF, etc.

Computer program code for carrying out operations of the presentdisclosure may be written in an object oriented programming languagesuch as Java, Smalltalk, C++ or the like. However, the computer programcode for carrying out operations of the present disclosure may also bewritten in conventional procedural programming languages, such as the“C” programming language or similar programming languages. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through a local area network/a widearea network/the Internet (e.g., network 14).

The present disclosure is described with reference to flowchartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products according to embodiments of the disclosure. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, may be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer/special purposecomputer/other programmable data processing apparatus, such that theinstructions, which execute via the processor of the computer or otherprogrammable data processing apparatus, create means for implementingthe functions/acts specified in the flowchart and/or block diagram blockor blocks.

These computer program instructions may also be stored in acomputer-readable memory that may direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

The flowcharts and block diagrams in the figures may illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustrations,and combinations of blocks in the block diagrams and/or flowchartillustrations, may be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

A number of implementations have been described. Having thus describedthe disclosure of the present application in detail and by reference toembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of thedisclosure defined in the appended claims.

What is claimed is:
 1. A computer-implemented method, executed on acomputing device, comprising: extracting acoustic metadata from asignal; converting the signal from the time domain to the featuredomain, thus defining feature-based voice data associated with thesignal; and processing the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata.
 2. Thecomputer-implemented method of claim 1, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes qualifying at least a portion ofthe feature-based voice data associated with the signal for one or moreof training data and adaptation data based upon, at least in part, theacoustic metadata.
 3. The computer-implemented method of claim 1,wherein processing the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata includesdisqualifying at least a portion of the feature-based voice dataassociated with the signal from one or more of training data andadaptation data based upon, at least in part, the acoustic metadata. 4.The computer-implemented method of claim 1, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes performing one or moregain-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata.
 5. The computer-implemented method of claim 1,wherein processing the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata includesperforming one or more rate-based augmentations on at least a portion ofthe feature-based voice data associated with the signal based upon, atleast in part, the acoustic metadata.
 6. The computer-implemented methodof claim 1, wherein processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadataincludes performing one or more audio feature-based augmentations on atleast a portion of the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata.
 7. Thecomputer-implemented method of claim 1, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes performing one or morereverberation-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.
 8. A computer program product residingon a non-transitory computer readable medium having a plurality ofinstructions stored thereon which, when executed by a processor, causethe processor to perform operations comprising: extracting acousticmetadata from a signal; converting the signal from the time domain tothe feature domain, thus defining feature-based voice data associatedwith the signal; and processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadata. 9.The computer program product of claim 8, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes qualifying at least a portion ofthe feature-based voice data associated with the signal for one or moreof training data and adaptation data based upon, at least in part, theacoustic metadata.
 10. The computer program product of claim 8, whereinprocessing the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata includes disqualifying atleast a portion of the feature-based voice data associated with thesignal from one or more of training data and adaptation data based upon,at least in part, the acoustic metadata.
 11. The computer programproduct of claim 8, wherein processing the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata includes performing one or more gain-based augmentations on atleast a portion of the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata.
 12. Thecomputer program product of claim 9, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes performing one or morerate-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata.
 13. The computer program product of claim 8, whereinprocessing the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata includes performing one ormore audio feature-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.
 14. The computer program product ofclaim 8, wherein processing the feature-based voice data associated withthe signal based upon, at least in part, the acoustic metadata includesperforming one or more reverberation-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata.
 15. A computing systemcomprising: a memory; and a processor configured to extract acousticmetadata from a signal, wherein the processor is further configured toconvert the signal from the time domain to the feature domain, thusdefining feature-based voice data associated with the signal, andwherein the processor is further configured to process the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata.
 16. The computing system of claim 15, whereinprocessing the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata includes qualifying atleast a portion of the feature-based voice data associated with thesignal for one or more of training data and adaptation data based upon,at least in part, the acoustic metadata.
 17. The computing system ofclaim 15, wherein processing the feature-based voice data associatedwith the signal based upon, at least in part, the acoustic metadataincludes disqualifying at least a portion of the feature-based voicedata associated with the signal from one or more of training data andadaptation data based upon, at least in part, the acoustic metadata. 18.The computing system of claim 15, wherein processing the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata includes performing one or more gain-basedaugmentations on at least a portion of the feature-based voice dataassociated with the signal based upon, at least in part, the acousticmetadata.
 19. The computing system of claim 15, wherein processing thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata includes performing one or morerate-based augmentations on at least a portion of the feature-basedvoice data associated with the signal based upon, at least in part, theacoustic metadata.
 20. The computing system of claim 15, whereinprocessing the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata includes performing one ormore audio feature-based augmentations on at least a portion of thefeature-based voice data associated with the signal based upon, at leastin part, the acoustic metadata.
 21. The computing system of claim 15,wherein processing the feature-based voice data associated with thesignal based upon, at least in part, the acoustic metadata includesperforming one or more reverberation-based augmentations on at least aportion of the feature-based voice data associated with the signal basedupon, at least in part, the acoustic metadata.